Managing Agricultural Water Impactswingolog.org/projects/water/water.pdfFinal Paper E497B—The...
Transcript of Managing Agricultural Water Impactswingolog.org/projects/water/water.pdfFinal Paper E497B—The...
Managing Agricultural Water
Impacts
Final Paper
E497BmdashThe Benjamin Franklin Scholars Capstone Course
Offered in conjunction with the Department of Multidisciplinary Studies
Elizabeth Covalla
Industrial EngineeringmdashPolitical Science
Chethan Pandarinath
Computer EngineeringmdashScience Technology and Society
James Williams
Mechanical EngineeringmdashScience Technology and Society
Jon Williams
Environmental EngineeringmdashPhilosophy
Andy Wingo
Nuclear EngineeringmdashPhysicsmdashSpanish
Supervised by Drs Joseph R Herkert and Jerome P Lavelle
North Carolina State University
Fall 2001
Copyright ccopy 2001 Elizabeth Covalla Chethan Pandarinath James Williams
Jon Williams Andy Wingo
Typeset by the authors with the LATEX2ε Documentation System
Abstract
This technology assessment explores the degree to which agriculture affects the quality and
quantity of water resources available in the United States The magnitude of agricultural
water impacts is quantified to the extent possible and selected impacts related to groundwa-
ter overdraft and surface water diversion are explored in detail Technological tools available
to help relieve agricultural water impacts are described as are policy tools available to the
Congress A list of priority policy options to help effect agricultural water resource sustain-
ability in the United States is presented and analyzed
Keyword List
agricultural water impacts policy options groundwater overdraft surface water diversion
non-pointsource pollution technology assessment best management practices resource de-
pletion
ii
Contents
1 Executive Summary 1
11 Introduction 1
12 Definitions 2
13 Problem Statement 3
14 Stakeholders 4
15 Problem Categories 5
16 Technology Tools 5
17 Priority Policy Options 6
2 Problem Background 7
21 The Challenge of Quantification 8
22 Agricultural Water Sources 10
221 Surface Water 10
222 Groundwater 11
23 Agricultural Water Use 13
231 Irrigation 14
24 Agricultural Water Discharge 16
241 Nitrates 17
242 Pesticides 19
25 Summary 21
iii
iv Managing Agricultural Water Impacts
3 Selected Problem Impacts 23
31 Impacts of Groundwater Overdraft 23
311 Higher Pumping Costs 23
312 Land Subsidence 24
313 Depletion of Surface Water 25
314 Degraded Aquifer Water Quality 25
32 Impacts of Surface Water Diversion 26
321 Habitat Loss 26
322 Decreased Aquifer Recharge 26
323 Municipal Supply Problems 27
324 Pollution Concentration 27
33 Second-Order Impacts 27
331 Increasing Water Price 27
332 Loss of Farm Production 28
333 Changes to Animal Agriculture 28
334 Failure of Local Economies 28
4 Technologies 31
41 Water Sources Increasing Quantity 31
411 Desalination 31
412 Dams and Reservoirs 32
413 Water Reuse 33
42 Water Uses Improving Efficiency 36
421 Irrigation 37
422 Water-Thrifty Crops 40
43 Water Discharge Reducing Pollution 40
5 Priority Policy Options 43
51 Policy Tools 43
Managing Agricultural Water Impacts v
511 Regulatory Tools 44
512 Subsidy Tools 45
513 Informational Tools 46
52 Policy Options 46
521 Quality-Focused Policies 47
522 Quantity-Focused Policies 48
523 Comprehensive Policies 51
vi
List of Tables
21 The agricultural water cycle Inputs and outputs 8
22 Water consumption by food type 16
41 The typical costs of desalination 32
42 Irrigation methods 37
vii
viii
List of Figures
21 Estimated use of water in the United States 1950ndash1990 10
22 Aquifer locations in the western United States 11
23 1990 irrigation withdrawals as the percent of total freshwater withdrawals 14
24 US pesticide usage in 1997 20
31 Subsidence due to groundwater overdraft California 1925-1992 24
ix
x
Chapter 1
Executive Summary
ldquoWhen the well is dry we know the worth of waterrdquo
Benjamin Franklin Poor Richardrsquos Almanac 1746
ldquoWater is a very good servant but it is a cruel masterrdquo
CGD Roberts Adrift in America 1891
ldquoIf the wars of this century were fought over oil the wars of the next century will
be fought over watermdashunless we change our approach to managing this precious
and vital resourcerdquo
Ismail Serageldin Vice President of the World Bank 1995
11 Introduction
Today at the advent of a new millenium the United States has been forced to undertake a
critical reexamination of national security policies Water resource management although
not traditionally at the vanguard of such issues is increasingly recognized around the world
as a crucial aspect of national security While the United States does not presently top the
list of water-scarce countries an examination of the available data casts into question the
security of water resources in the future Water use trends in the United States indicate
1
2 Managing Agricultural Water Impacts
that the country will soon face a crisis in both water quality and water quantity unless
current policies and practices are amended
This problem-based technology assessment seeks to analyze the impacts of agricultural
water use in the United States and to propose solutions to effectively manage agricultural
water resources The goals of this assessment are as follows
1 Establish the problem as quantitatively as possible
2 Provide background and context for the problem aspects
3 Describe the direct and higher-order impacts of the problem
4 Examine the technologies available to solve the problem
5 Discuss the policy tools available to solve the problem
6 Predict the first and higher-order impacts of potential technology and policy solutions
12 Definitions
This technology assessment makes use of several terms and abbreviations In order to be
precise in the use of terms the following definitions are provided
bull Sustainability - Seeking to meet the needs of the present without compromising the
ability of future generations to meet their own needs
bull Pointsource - Pollution from a geographically localized discharge For example
a smokestack represents an atmospheric pointsource and a sewage treatment plant
represents an aquatic pointsource
bull Non-pointsource - Pollution from a geographically distributed discharge For ex-
ample land application of fertilizers is a non-pointsource discharge of nitrogen and
other nutrients
Managing Agricultural Water Impacts 3
bull Effluent - Any pollution-containing discharge of water from an engineered process
such as irrigation industrial production or municipal sewage treatment
bull Aquifer - A porous subterranean region saturated with groundwater
bull Surface water - Water available in streams rivers lakes and reservoirs
bull Best management practices (BMPs) - Ways in which agricultural production
methods can be altered to minimize negative water impacts
13 Problem Statement
Agricultural operations including animal and crop farming are important contributors to
the depletion of water resource quality and quantity in the United States Agriculture
represents approximately 40 of total US water demand and irrigation is the largest
consumptive water use Agricultural operations have been identified by the Environmental
Protection Agency as the leading source of water quality impairment to rivers and lakes
While reliable quantification of specific water quality and quantity impacts is gener-
ally unavailable the water resource research community agrees that the following crucial
problems are directly relevant to agriculture
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater overpumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
4 Managing Agricultural Water Impacts
bull Present United States water policies are insufficient to ensure future water supply
security
This technology assessment explores the options available to the federal government to
effect a move toward sustainable agricultural water management in light of the problems
listed above
14 Stakeholders
Because water is necessary for life all living things are stakeholders in this technology
assessment in the broadest possible sense For the purposes of this report stakeholders
are classified into groups that can be expected to share similar goals regarding agricultural
water resource policies The rights-holders most directly affected by the issues examined in
this report are
bull Agricultural producers and related industries - Farmers and the industries who
supply farm-related products are primary stakeholders Producers directly influence
water resources through agricultural withdrawal use and discharge
bull Municipal water users - The second-largest water demand after agriculture is mu-
nicipalities Clean drinking water is distributed to residences as well as industrial
operations Municipalities often compete directly with agriculture in water-scarce
regions
bull Federal state and local government - Water resources are managed by a variety
of governmental agencies Because water is a resource crucial to national security the
government is a central stakeholder Laws respecting water are passed at all levels of
government with corresponding jurisdictions of enforcement
bull Indigenous groups - Treaty agreements allocate water rights to indigenous groups
across the country In some regions these stakeholders have been under pressure from
agriculture and municipalities to relinquish their claims
Managing Agricultural Water Impacts 5
bull Environmental advocacy groups - Water quality and quantity issues related to
agriculture have wide-ranging impacts on the environment Individuals seeking to
protect the environment constitute a stakeholder group that regularly participates in
the formulation of US policy
bull US trade partners - As an importer and exporter of products on the world market
changes in the cost or quantity of production of agricultural goods in the United States
will affect other nations
15 Problem Categories
The problems associated with agricultural water use are arranged in this technology as-
sessment in terms of the water cycle of the United States This water cycle begins with
a source proceeds to a use and terminates with a discharge After providing background
and context for the broad range of agricultural water problems the report details some es-
pecially important first-order and higher-order impacts which result from current national
policies and practices The selected impacts focus on the withdrawal of groundwater and
the diversion of surface water for agricultural use
16 Technology Tools
Chapter 4 offers a study of the technologies available for increasing the quantity of water
available increasing the efficiency of use and limiting the impacts of agricultural pollution
The state of the art in agricultural technology is presented in order to provide background
for technology-based policy recommendations Ultimately most of the policies offered by
this technology assessment are not technology-focused since broader structural changes in
agricultural production are found to be needed to bring about water resource sustainability
6 Managing Agricultural Water Impacts
17 Priority Policy Options
This technology assessment concludes with an examination of eleven priority policy options
available to the Congress to help bring about sustainable water management in the United
States The policy options are called ldquopriorityrdquo because they are identified as those most
likely to be highly effective or cost-efficient in acheiving national water resource sustainabil-
ity These policies were developed through a synthesis of the information presented in the
following chapters along with an understanding of the type of policy tools available to the
Congress The priority policy option are analyzed in terms of their anticipated first-order
and higher-order policy impacts
Chapter 2
Problem Background
To establish agricultural water management as a priority subject for national policy atten-
tion this report first examines the historical context present situation and quantitative
significance of selected water resource problems in the United States This chapter is orga-
nized by following the mass flow of water from source to use to discharge
bull SourcesmdashSurface water and groundwater the two most significant water sources
for agriculture are described along with national usage trends and implications for
specific regions of the country
bull UsesmdashIrrigation the primary use of water withdrawn for agricultural production is
quantified and the potential for increases in efficiency is discussed
bull DischargesmdashThe fate of agricultural water supplies is examined with regard to quan-
tity loss and pollution contributions
Before an analysis of these areas it is important to understand the degree to which a
national water balance can be quantified By understanding the difficulties involved with
modeling the water cycle and using this data to project future water trends policy makers
will be better prepared to appreciate and to act on the information contained in this report
7
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Copyright ccopy 2001 Elizabeth Covalla Chethan Pandarinath James Williams
Jon Williams Andy Wingo
Typeset by the authors with the LATEX2ε Documentation System
Abstract
This technology assessment explores the degree to which agriculture affects the quality and
quantity of water resources available in the United States The magnitude of agricultural
water impacts is quantified to the extent possible and selected impacts related to groundwa-
ter overdraft and surface water diversion are explored in detail Technological tools available
to help relieve agricultural water impacts are described as are policy tools available to the
Congress A list of priority policy options to help effect agricultural water resource sustain-
ability in the United States is presented and analyzed
Keyword List
agricultural water impacts policy options groundwater overdraft surface water diversion
non-pointsource pollution technology assessment best management practices resource de-
pletion
ii
Contents
1 Executive Summary 1
11 Introduction 1
12 Definitions 2
13 Problem Statement 3
14 Stakeholders 4
15 Problem Categories 5
16 Technology Tools 5
17 Priority Policy Options 6
2 Problem Background 7
21 The Challenge of Quantification 8
22 Agricultural Water Sources 10
221 Surface Water 10
222 Groundwater 11
23 Agricultural Water Use 13
231 Irrigation 14
24 Agricultural Water Discharge 16
241 Nitrates 17
242 Pesticides 19
25 Summary 21
iii
iv Managing Agricultural Water Impacts
3 Selected Problem Impacts 23
31 Impacts of Groundwater Overdraft 23
311 Higher Pumping Costs 23
312 Land Subsidence 24
313 Depletion of Surface Water 25
314 Degraded Aquifer Water Quality 25
32 Impacts of Surface Water Diversion 26
321 Habitat Loss 26
322 Decreased Aquifer Recharge 26
323 Municipal Supply Problems 27
324 Pollution Concentration 27
33 Second-Order Impacts 27
331 Increasing Water Price 27
332 Loss of Farm Production 28
333 Changes to Animal Agriculture 28
334 Failure of Local Economies 28
4 Technologies 31
41 Water Sources Increasing Quantity 31
411 Desalination 31
412 Dams and Reservoirs 32
413 Water Reuse 33
42 Water Uses Improving Efficiency 36
421 Irrigation 37
422 Water-Thrifty Crops 40
43 Water Discharge Reducing Pollution 40
5 Priority Policy Options 43
51 Policy Tools 43
Managing Agricultural Water Impacts v
511 Regulatory Tools 44
512 Subsidy Tools 45
513 Informational Tools 46
52 Policy Options 46
521 Quality-Focused Policies 47
522 Quantity-Focused Policies 48
523 Comprehensive Policies 51
vi
List of Tables
21 The agricultural water cycle Inputs and outputs 8
22 Water consumption by food type 16
41 The typical costs of desalination 32
42 Irrigation methods 37
vii
viii
List of Figures
21 Estimated use of water in the United States 1950ndash1990 10
22 Aquifer locations in the western United States 11
23 1990 irrigation withdrawals as the percent of total freshwater withdrawals 14
24 US pesticide usage in 1997 20
31 Subsidence due to groundwater overdraft California 1925-1992 24
ix
x
Chapter 1
Executive Summary
ldquoWhen the well is dry we know the worth of waterrdquo
Benjamin Franklin Poor Richardrsquos Almanac 1746
ldquoWater is a very good servant but it is a cruel masterrdquo
CGD Roberts Adrift in America 1891
ldquoIf the wars of this century were fought over oil the wars of the next century will
be fought over watermdashunless we change our approach to managing this precious
and vital resourcerdquo
Ismail Serageldin Vice President of the World Bank 1995
11 Introduction
Today at the advent of a new millenium the United States has been forced to undertake a
critical reexamination of national security policies Water resource management although
not traditionally at the vanguard of such issues is increasingly recognized around the world
as a crucial aspect of national security While the United States does not presently top the
list of water-scarce countries an examination of the available data casts into question the
security of water resources in the future Water use trends in the United States indicate
1
2 Managing Agricultural Water Impacts
that the country will soon face a crisis in both water quality and water quantity unless
current policies and practices are amended
This problem-based technology assessment seeks to analyze the impacts of agricultural
water use in the United States and to propose solutions to effectively manage agricultural
water resources The goals of this assessment are as follows
1 Establish the problem as quantitatively as possible
2 Provide background and context for the problem aspects
3 Describe the direct and higher-order impacts of the problem
4 Examine the technologies available to solve the problem
5 Discuss the policy tools available to solve the problem
6 Predict the first and higher-order impacts of potential technology and policy solutions
12 Definitions
This technology assessment makes use of several terms and abbreviations In order to be
precise in the use of terms the following definitions are provided
bull Sustainability - Seeking to meet the needs of the present without compromising the
ability of future generations to meet their own needs
bull Pointsource - Pollution from a geographically localized discharge For example
a smokestack represents an atmospheric pointsource and a sewage treatment plant
represents an aquatic pointsource
bull Non-pointsource - Pollution from a geographically distributed discharge For ex-
ample land application of fertilizers is a non-pointsource discharge of nitrogen and
other nutrients
Managing Agricultural Water Impacts 3
bull Effluent - Any pollution-containing discharge of water from an engineered process
such as irrigation industrial production or municipal sewage treatment
bull Aquifer - A porous subterranean region saturated with groundwater
bull Surface water - Water available in streams rivers lakes and reservoirs
bull Best management practices (BMPs) - Ways in which agricultural production
methods can be altered to minimize negative water impacts
13 Problem Statement
Agricultural operations including animal and crop farming are important contributors to
the depletion of water resource quality and quantity in the United States Agriculture
represents approximately 40 of total US water demand and irrigation is the largest
consumptive water use Agricultural operations have been identified by the Environmental
Protection Agency as the leading source of water quality impairment to rivers and lakes
While reliable quantification of specific water quality and quantity impacts is gener-
ally unavailable the water resource research community agrees that the following crucial
problems are directly relevant to agriculture
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater overpumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
4 Managing Agricultural Water Impacts
bull Present United States water policies are insufficient to ensure future water supply
security
This technology assessment explores the options available to the federal government to
effect a move toward sustainable agricultural water management in light of the problems
listed above
14 Stakeholders
Because water is necessary for life all living things are stakeholders in this technology
assessment in the broadest possible sense For the purposes of this report stakeholders
are classified into groups that can be expected to share similar goals regarding agricultural
water resource policies The rights-holders most directly affected by the issues examined in
this report are
bull Agricultural producers and related industries - Farmers and the industries who
supply farm-related products are primary stakeholders Producers directly influence
water resources through agricultural withdrawal use and discharge
bull Municipal water users - The second-largest water demand after agriculture is mu-
nicipalities Clean drinking water is distributed to residences as well as industrial
operations Municipalities often compete directly with agriculture in water-scarce
regions
bull Federal state and local government - Water resources are managed by a variety
of governmental agencies Because water is a resource crucial to national security the
government is a central stakeholder Laws respecting water are passed at all levels of
government with corresponding jurisdictions of enforcement
bull Indigenous groups - Treaty agreements allocate water rights to indigenous groups
across the country In some regions these stakeholders have been under pressure from
agriculture and municipalities to relinquish their claims
Managing Agricultural Water Impacts 5
bull Environmental advocacy groups - Water quality and quantity issues related to
agriculture have wide-ranging impacts on the environment Individuals seeking to
protect the environment constitute a stakeholder group that regularly participates in
the formulation of US policy
bull US trade partners - As an importer and exporter of products on the world market
changes in the cost or quantity of production of agricultural goods in the United States
will affect other nations
15 Problem Categories
The problems associated with agricultural water use are arranged in this technology as-
sessment in terms of the water cycle of the United States This water cycle begins with
a source proceeds to a use and terminates with a discharge After providing background
and context for the broad range of agricultural water problems the report details some es-
pecially important first-order and higher-order impacts which result from current national
policies and practices The selected impacts focus on the withdrawal of groundwater and
the diversion of surface water for agricultural use
16 Technology Tools
Chapter 4 offers a study of the technologies available for increasing the quantity of water
available increasing the efficiency of use and limiting the impacts of agricultural pollution
The state of the art in agricultural technology is presented in order to provide background
for technology-based policy recommendations Ultimately most of the policies offered by
this technology assessment are not technology-focused since broader structural changes in
agricultural production are found to be needed to bring about water resource sustainability
6 Managing Agricultural Water Impacts
17 Priority Policy Options
This technology assessment concludes with an examination of eleven priority policy options
available to the Congress to help bring about sustainable water management in the United
States The policy options are called ldquopriorityrdquo because they are identified as those most
likely to be highly effective or cost-efficient in acheiving national water resource sustainabil-
ity These policies were developed through a synthesis of the information presented in the
following chapters along with an understanding of the type of policy tools available to the
Congress The priority policy option are analyzed in terms of their anticipated first-order
and higher-order policy impacts
Chapter 2
Problem Background
To establish agricultural water management as a priority subject for national policy atten-
tion this report first examines the historical context present situation and quantitative
significance of selected water resource problems in the United States This chapter is orga-
nized by following the mass flow of water from source to use to discharge
bull SourcesmdashSurface water and groundwater the two most significant water sources
for agriculture are described along with national usage trends and implications for
specific regions of the country
bull UsesmdashIrrigation the primary use of water withdrawn for agricultural production is
quantified and the potential for increases in efficiency is discussed
bull DischargesmdashThe fate of agricultural water supplies is examined with regard to quan-
tity loss and pollution contributions
Before an analysis of these areas it is important to understand the degree to which a
national water balance can be quantified By understanding the difficulties involved with
modeling the water cycle and using this data to project future water trends policy makers
will be better prepared to appreciate and to act on the information contained in this report
7
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Abstract
This technology assessment explores the degree to which agriculture affects the quality and
quantity of water resources available in the United States The magnitude of agricultural
water impacts is quantified to the extent possible and selected impacts related to groundwa-
ter overdraft and surface water diversion are explored in detail Technological tools available
to help relieve agricultural water impacts are described as are policy tools available to the
Congress A list of priority policy options to help effect agricultural water resource sustain-
ability in the United States is presented and analyzed
Keyword List
agricultural water impacts policy options groundwater overdraft surface water diversion
non-pointsource pollution technology assessment best management practices resource de-
pletion
ii
Contents
1 Executive Summary 1
11 Introduction 1
12 Definitions 2
13 Problem Statement 3
14 Stakeholders 4
15 Problem Categories 5
16 Technology Tools 5
17 Priority Policy Options 6
2 Problem Background 7
21 The Challenge of Quantification 8
22 Agricultural Water Sources 10
221 Surface Water 10
222 Groundwater 11
23 Agricultural Water Use 13
231 Irrigation 14
24 Agricultural Water Discharge 16
241 Nitrates 17
242 Pesticides 19
25 Summary 21
iii
iv Managing Agricultural Water Impacts
3 Selected Problem Impacts 23
31 Impacts of Groundwater Overdraft 23
311 Higher Pumping Costs 23
312 Land Subsidence 24
313 Depletion of Surface Water 25
314 Degraded Aquifer Water Quality 25
32 Impacts of Surface Water Diversion 26
321 Habitat Loss 26
322 Decreased Aquifer Recharge 26
323 Municipal Supply Problems 27
324 Pollution Concentration 27
33 Second-Order Impacts 27
331 Increasing Water Price 27
332 Loss of Farm Production 28
333 Changes to Animal Agriculture 28
334 Failure of Local Economies 28
4 Technologies 31
41 Water Sources Increasing Quantity 31
411 Desalination 31
412 Dams and Reservoirs 32
413 Water Reuse 33
42 Water Uses Improving Efficiency 36
421 Irrigation 37
422 Water-Thrifty Crops 40
43 Water Discharge Reducing Pollution 40
5 Priority Policy Options 43
51 Policy Tools 43
Managing Agricultural Water Impacts v
511 Regulatory Tools 44
512 Subsidy Tools 45
513 Informational Tools 46
52 Policy Options 46
521 Quality-Focused Policies 47
522 Quantity-Focused Policies 48
523 Comprehensive Policies 51
vi
List of Tables
21 The agricultural water cycle Inputs and outputs 8
22 Water consumption by food type 16
41 The typical costs of desalination 32
42 Irrigation methods 37
vii
viii
List of Figures
21 Estimated use of water in the United States 1950ndash1990 10
22 Aquifer locations in the western United States 11
23 1990 irrigation withdrawals as the percent of total freshwater withdrawals 14
24 US pesticide usage in 1997 20
31 Subsidence due to groundwater overdraft California 1925-1992 24
ix
x
Chapter 1
Executive Summary
ldquoWhen the well is dry we know the worth of waterrdquo
Benjamin Franklin Poor Richardrsquos Almanac 1746
ldquoWater is a very good servant but it is a cruel masterrdquo
CGD Roberts Adrift in America 1891
ldquoIf the wars of this century were fought over oil the wars of the next century will
be fought over watermdashunless we change our approach to managing this precious
and vital resourcerdquo
Ismail Serageldin Vice President of the World Bank 1995
11 Introduction
Today at the advent of a new millenium the United States has been forced to undertake a
critical reexamination of national security policies Water resource management although
not traditionally at the vanguard of such issues is increasingly recognized around the world
as a crucial aspect of national security While the United States does not presently top the
list of water-scarce countries an examination of the available data casts into question the
security of water resources in the future Water use trends in the United States indicate
1
2 Managing Agricultural Water Impacts
that the country will soon face a crisis in both water quality and water quantity unless
current policies and practices are amended
This problem-based technology assessment seeks to analyze the impacts of agricultural
water use in the United States and to propose solutions to effectively manage agricultural
water resources The goals of this assessment are as follows
1 Establish the problem as quantitatively as possible
2 Provide background and context for the problem aspects
3 Describe the direct and higher-order impacts of the problem
4 Examine the technologies available to solve the problem
5 Discuss the policy tools available to solve the problem
6 Predict the first and higher-order impacts of potential technology and policy solutions
12 Definitions
This technology assessment makes use of several terms and abbreviations In order to be
precise in the use of terms the following definitions are provided
bull Sustainability - Seeking to meet the needs of the present without compromising the
ability of future generations to meet their own needs
bull Pointsource - Pollution from a geographically localized discharge For example
a smokestack represents an atmospheric pointsource and a sewage treatment plant
represents an aquatic pointsource
bull Non-pointsource - Pollution from a geographically distributed discharge For ex-
ample land application of fertilizers is a non-pointsource discharge of nitrogen and
other nutrients
Managing Agricultural Water Impacts 3
bull Effluent - Any pollution-containing discharge of water from an engineered process
such as irrigation industrial production or municipal sewage treatment
bull Aquifer - A porous subterranean region saturated with groundwater
bull Surface water - Water available in streams rivers lakes and reservoirs
bull Best management practices (BMPs) - Ways in which agricultural production
methods can be altered to minimize negative water impacts
13 Problem Statement
Agricultural operations including animal and crop farming are important contributors to
the depletion of water resource quality and quantity in the United States Agriculture
represents approximately 40 of total US water demand and irrigation is the largest
consumptive water use Agricultural operations have been identified by the Environmental
Protection Agency as the leading source of water quality impairment to rivers and lakes
While reliable quantification of specific water quality and quantity impacts is gener-
ally unavailable the water resource research community agrees that the following crucial
problems are directly relevant to agriculture
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater overpumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
4 Managing Agricultural Water Impacts
bull Present United States water policies are insufficient to ensure future water supply
security
This technology assessment explores the options available to the federal government to
effect a move toward sustainable agricultural water management in light of the problems
listed above
14 Stakeholders
Because water is necessary for life all living things are stakeholders in this technology
assessment in the broadest possible sense For the purposes of this report stakeholders
are classified into groups that can be expected to share similar goals regarding agricultural
water resource policies The rights-holders most directly affected by the issues examined in
this report are
bull Agricultural producers and related industries - Farmers and the industries who
supply farm-related products are primary stakeholders Producers directly influence
water resources through agricultural withdrawal use and discharge
bull Municipal water users - The second-largest water demand after agriculture is mu-
nicipalities Clean drinking water is distributed to residences as well as industrial
operations Municipalities often compete directly with agriculture in water-scarce
regions
bull Federal state and local government - Water resources are managed by a variety
of governmental agencies Because water is a resource crucial to national security the
government is a central stakeholder Laws respecting water are passed at all levels of
government with corresponding jurisdictions of enforcement
bull Indigenous groups - Treaty agreements allocate water rights to indigenous groups
across the country In some regions these stakeholders have been under pressure from
agriculture and municipalities to relinquish their claims
Managing Agricultural Water Impacts 5
bull Environmental advocacy groups - Water quality and quantity issues related to
agriculture have wide-ranging impacts on the environment Individuals seeking to
protect the environment constitute a stakeholder group that regularly participates in
the formulation of US policy
bull US trade partners - As an importer and exporter of products on the world market
changes in the cost or quantity of production of agricultural goods in the United States
will affect other nations
15 Problem Categories
The problems associated with agricultural water use are arranged in this technology as-
sessment in terms of the water cycle of the United States This water cycle begins with
a source proceeds to a use and terminates with a discharge After providing background
and context for the broad range of agricultural water problems the report details some es-
pecially important first-order and higher-order impacts which result from current national
policies and practices The selected impacts focus on the withdrawal of groundwater and
the diversion of surface water for agricultural use
16 Technology Tools
Chapter 4 offers a study of the technologies available for increasing the quantity of water
available increasing the efficiency of use and limiting the impacts of agricultural pollution
The state of the art in agricultural technology is presented in order to provide background
for technology-based policy recommendations Ultimately most of the policies offered by
this technology assessment are not technology-focused since broader structural changes in
agricultural production are found to be needed to bring about water resource sustainability
6 Managing Agricultural Water Impacts
17 Priority Policy Options
This technology assessment concludes with an examination of eleven priority policy options
available to the Congress to help bring about sustainable water management in the United
States The policy options are called ldquopriorityrdquo because they are identified as those most
likely to be highly effective or cost-efficient in acheiving national water resource sustainabil-
ity These policies were developed through a synthesis of the information presented in the
following chapters along with an understanding of the type of policy tools available to the
Congress The priority policy option are analyzed in terms of their anticipated first-order
and higher-order policy impacts
Chapter 2
Problem Background
To establish agricultural water management as a priority subject for national policy atten-
tion this report first examines the historical context present situation and quantitative
significance of selected water resource problems in the United States This chapter is orga-
nized by following the mass flow of water from source to use to discharge
bull SourcesmdashSurface water and groundwater the two most significant water sources
for agriculture are described along with national usage trends and implications for
specific regions of the country
bull UsesmdashIrrigation the primary use of water withdrawn for agricultural production is
quantified and the potential for increases in efficiency is discussed
bull DischargesmdashThe fate of agricultural water supplies is examined with regard to quan-
tity loss and pollution contributions
Before an analysis of these areas it is important to understand the degree to which a
national water balance can be quantified By understanding the difficulties involved with
modeling the water cycle and using this data to project future water trends policy makers
will be better prepared to appreciate and to act on the information contained in this report
7
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
ii
Contents
1 Executive Summary 1
11 Introduction 1
12 Definitions 2
13 Problem Statement 3
14 Stakeholders 4
15 Problem Categories 5
16 Technology Tools 5
17 Priority Policy Options 6
2 Problem Background 7
21 The Challenge of Quantification 8
22 Agricultural Water Sources 10
221 Surface Water 10
222 Groundwater 11
23 Agricultural Water Use 13
231 Irrigation 14
24 Agricultural Water Discharge 16
241 Nitrates 17
242 Pesticides 19
25 Summary 21
iii
iv Managing Agricultural Water Impacts
3 Selected Problem Impacts 23
31 Impacts of Groundwater Overdraft 23
311 Higher Pumping Costs 23
312 Land Subsidence 24
313 Depletion of Surface Water 25
314 Degraded Aquifer Water Quality 25
32 Impacts of Surface Water Diversion 26
321 Habitat Loss 26
322 Decreased Aquifer Recharge 26
323 Municipal Supply Problems 27
324 Pollution Concentration 27
33 Second-Order Impacts 27
331 Increasing Water Price 27
332 Loss of Farm Production 28
333 Changes to Animal Agriculture 28
334 Failure of Local Economies 28
4 Technologies 31
41 Water Sources Increasing Quantity 31
411 Desalination 31
412 Dams and Reservoirs 32
413 Water Reuse 33
42 Water Uses Improving Efficiency 36
421 Irrigation 37
422 Water-Thrifty Crops 40
43 Water Discharge Reducing Pollution 40
5 Priority Policy Options 43
51 Policy Tools 43
Managing Agricultural Water Impacts v
511 Regulatory Tools 44
512 Subsidy Tools 45
513 Informational Tools 46
52 Policy Options 46
521 Quality-Focused Policies 47
522 Quantity-Focused Policies 48
523 Comprehensive Policies 51
vi
List of Tables
21 The agricultural water cycle Inputs and outputs 8
22 Water consumption by food type 16
41 The typical costs of desalination 32
42 Irrigation methods 37
vii
viii
List of Figures
21 Estimated use of water in the United States 1950ndash1990 10
22 Aquifer locations in the western United States 11
23 1990 irrigation withdrawals as the percent of total freshwater withdrawals 14
24 US pesticide usage in 1997 20
31 Subsidence due to groundwater overdraft California 1925-1992 24
ix
x
Chapter 1
Executive Summary
ldquoWhen the well is dry we know the worth of waterrdquo
Benjamin Franklin Poor Richardrsquos Almanac 1746
ldquoWater is a very good servant but it is a cruel masterrdquo
CGD Roberts Adrift in America 1891
ldquoIf the wars of this century were fought over oil the wars of the next century will
be fought over watermdashunless we change our approach to managing this precious
and vital resourcerdquo
Ismail Serageldin Vice President of the World Bank 1995
11 Introduction
Today at the advent of a new millenium the United States has been forced to undertake a
critical reexamination of national security policies Water resource management although
not traditionally at the vanguard of such issues is increasingly recognized around the world
as a crucial aspect of national security While the United States does not presently top the
list of water-scarce countries an examination of the available data casts into question the
security of water resources in the future Water use trends in the United States indicate
1
2 Managing Agricultural Water Impacts
that the country will soon face a crisis in both water quality and water quantity unless
current policies and practices are amended
This problem-based technology assessment seeks to analyze the impacts of agricultural
water use in the United States and to propose solutions to effectively manage agricultural
water resources The goals of this assessment are as follows
1 Establish the problem as quantitatively as possible
2 Provide background and context for the problem aspects
3 Describe the direct and higher-order impacts of the problem
4 Examine the technologies available to solve the problem
5 Discuss the policy tools available to solve the problem
6 Predict the first and higher-order impacts of potential technology and policy solutions
12 Definitions
This technology assessment makes use of several terms and abbreviations In order to be
precise in the use of terms the following definitions are provided
bull Sustainability - Seeking to meet the needs of the present without compromising the
ability of future generations to meet their own needs
bull Pointsource - Pollution from a geographically localized discharge For example
a smokestack represents an atmospheric pointsource and a sewage treatment plant
represents an aquatic pointsource
bull Non-pointsource - Pollution from a geographically distributed discharge For ex-
ample land application of fertilizers is a non-pointsource discharge of nitrogen and
other nutrients
Managing Agricultural Water Impacts 3
bull Effluent - Any pollution-containing discharge of water from an engineered process
such as irrigation industrial production or municipal sewage treatment
bull Aquifer - A porous subterranean region saturated with groundwater
bull Surface water - Water available in streams rivers lakes and reservoirs
bull Best management practices (BMPs) - Ways in which agricultural production
methods can be altered to minimize negative water impacts
13 Problem Statement
Agricultural operations including animal and crop farming are important contributors to
the depletion of water resource quality and quantity in the United States Agriculture
represents approximately 40 of total US water demand and irrigation is the largest
consumptive water use Agricultural operations have been identified by the Environmental
Protection Agency as the leading source of water quality impairment to rivers and lakes
While reliable quantification of specific water quality and quantity impacts is gener-
ally unavailable the water resource research community agrees that the following crucial
problems are directly relevant to agriculture
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater overpumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
4 Managing Agricultural Water Impacts
bull Present United States water policies are insufficient to ensure future water supply
security
This technology assessment explores the options available to the federal government to
effect a move toward sustainable agricultural water management in light of the problems
listed above
14 Stakeholders
Because water is necessary for life all living things are stakeholders in this technology
assessment in the broadest possible sense For the purposes of this report stakeholders
are classified into groups that can be expected to share similar goals regarding agricultural
water resource policies The rights-holders most directly affected by the issues examined in
this report are
bull Agricultural producers and related industries - Farmers and the industries who
supply farm-related products are primary stakeholders Producers directly influence
water resources through agricultural withdrawal use and discharge
bull Municipal water users - The second-largest water demand after agriculture is mu-
nicipalities Clean drinking water is distributed to residences as well as industrial
operations Municipalities often compete directly with agriculture in water-scarce
regions
bull Federal state and local government - Water resources are managed by a variety
of governmental agencies Because water is a resource crucial to national security the
government is a central stakeholder Laws respecting water are passed at all levels of
government with corresponding jurisdictions of enforcement
bull Indigenous groups - Treaty agreements allocate water rights to indigenous groups
across the country In some regions these stakeholders have been under pressure from
agriculture and municipalities to relinquish their claims
Managing Agricultural Water Impacts 5
bull Environmental advocacy groups - Water quality and quantity issues related to
agriculture have wide-ranging impacts on the environment Individuals seeking to
protect the environment constitute a stakeholder group that regularly participates in
the formulation of US policy
bull US trade partners - As an importer and exporter of products on the world market
changes in the cost or quantity of production of agricultural goods in the United States
will affect other nations
15 Problem Categories
The problems associated with agricultural water use are arranged in this technology as-
sessment in terms of the water cycle of the United States This water cycle begins with
a source proceeds to a use and terminates with a discharge After providing background
and context for the broad range of agricultural water problems the report details some es-
pecially important first-order and higher-order impacts which result from current national
policies and practices The selected impacts focus on the withdrawal of groundwater and
the diversion of surface water for agricultural use
16 Technology Tools
Chapter 4 offers a study of the technologies available for increasing the quantity of water
available increasing the efficiency of use and limiting the impacts of agricultural pollution
The state of the art in agricultural technology is presented in order to provide background
for technology-based policy recommendations Ultimately most of the policies offered by
this technology assessment are not technology-focused since broader structural changes in
agricultural production are found to be needed to bring about water resource sustainability
6 Managing Agricultural Water Impacts
17 Priority Policy Options
This technology assessment concludes with an examination of eleven priority policy options
available to the Congress to help bring about sustainable water management in the United
States The policy options are called ldquopriorityrdquo because they are identified as those most
likely to be highly effective or cost-efficient in acheiving national water resource sustainabil-
ity These policies were developed through a synthesis of the information presented in the
following chapters along with an understanding of the type of policy tools available to the
Congress The priority policy option are analyzed in terms of their anticipated first-order
and higher-order policy impacts
Chapter 2
Problem Background
To establish agricultural water management as a priority subject for national policy atten-
tion this report first examines the historical context present situation and quantitative
significance of selected water resource problems in the United States This chapter is orga-
nized by following the mass flow of water from source to use to discharge
bull SourcesmdashSurface water and groundwater the two most significant water sources
for agriculture are described along with national usage trends and implications for
specific regions of the country
bull UsesmdashIrrigation the primary use of water withdrawn for agricultural production is
quantified and the potential for increases in efficiency is discussed
bull DischargesmdashThe fate of agricultural water supplies is examined with regard to quan-
tity loss and pollution contributions
Before an analysis of these areas it is important to understand the degree to which a
national water balance can be quantified By understanding the difficulties involved with
modeling the water cycle and using this data to project future water trends policy makers
will be better prepared to appreciate and to act on the information contained in this report
7
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Contents
1 Executive Summary 1
11 Introduction 1
12 Definitions 2
13 Problem Statement 3
14 Stakeholders 4
15 Problem Categories 5
16 Technology Tools 5
17 Priority Policy Options 6
2 Problem Background 7
21 The Challenge of Quantification 8
22 Agricultural Water Sources 10
221 Surface Water 10
222 Groundwater 11
23 Agricultural Water Use 13
231 Irrigation 14
24 Agricultural Water Discharge 16
241 Nitrates 17
242 Pesticides 19
25 Summary 21
iii
iv Managing Agricultural Water Impacts
3 Selected Problem Impacts 23
31 Impacts of Groundwater Overdraft 23
311 Higher Pumping Costs 23
312 Land Subsidence 24
313 Depletion of Surface Water 25
314 Degraded Aquifer Water Quality 25
32 Impacts of Surface Water Diversion 26
321 Habitat Loss 26
322 Decreased Aquifer Recharge 26
323 Municipal Supply Problems 27
324 Pollution Concentration 27
33 Second-Order Impacts 27
331 Increasing Water Price 27
332 Loss of Farm Production 28
333 Changes to Animal Agriculture 28
334 Failure of Local Economies 28
4 Technologies 31
41 Water Sources Increasing Quantity 31
411 Desalination 31
412 Dams and Reservoirs 32
413 Water Reuse 33
42 Water Uses Improving Efficiency 36
421 Irrigation 37
422 Water-Thrifty Crops 40
43 Water Discharge Reducing Pollution 40
5 Priority Policy Options 43
51 Policy Tools 43
Managing Agricultural Water Impacts v
511 Regulatory Tools 44
512 Subsidy Tools 45
513 Informational Tools 46
52 Policy Options 46
521 Quality-Focused Policies 47
522 Quantity-Focused Policies 48
523 Comprehensive Policies 51
vi
List of Tables
21 The agricultural water cycle Inputs and outputs 8
22 Water consumption by food type 16
41 The typical costs of desalination 32
42 Irrigation methods 37
vii
viii
List of Figures
21 Estimated use of water in the United States 1950ndash1990 10
22 Aquifer locations in the western United States 11
23 1990 irrigation withdrawals as the percent of total freshwater withdrawals 14
24 US pesticide usage in 1997 20
31 Subsidence due to groundwater overdraft California 1925-1992 24
ix
x
Chapter 1
Executive Summary
ldquoWhen the well is dry we know the worth of waterrdquo
Benjamin Franklin Poor Richardrsquos Almanac 1746
ldquoWater is a very good servant but it is a cruel masterrdquo
CGD Roberts Adrift in America 1891
ldquoIf the wars of this century were fought over oil the wars of the next century will
be fought over watermdashunless we change our approach to managing this precious
and vital resourcerdquo
Ismail Serageldin Vice President of the World Bank 1995
11 Introduction
Today at the advent of a new millenium the United States has been forced to undertake a
critical reexamination of national security policies Water resource management although
not traditionally at the vanguard of such issues is increasingly recognized around the world
as a crucial aspect of national security While the United States does not presently top the
list of water-scarce countries an examination of the available data casts into question the
security of water resources in the future Water use trends in the United States indicate
1
2 Managing Agricultural Water Impacts
that the country will soon face a crisis in both water quality and water quantity unless
current policies and practices are amended
This problem-based technology assessment seeks to analyze the impacts of agricultural
water use in the United States and to propose solutions to effectively manage agricultural
water resources The goals of this assessment are as follows
1 Establish the problem as quantitatively as possible
2 Provide background and context for the problem aspects
3 Describe the direct and higher-order impacts of the problem
4 Examine the technologies available to solve the problem
5 Discuss the policy tools available to solve the problem
6 Predict the first and higher-order impacts of potential technology and policy solutions
12 Definitions
This technology assessment makes use of several terms and abbreviations In order to be
precise in the use of terms the following definitions are provided
bull Sustainability - Seeking to meet the needs of the present without compromising the
ability of future generations to meet their own needs
bull Pointsource - Pollution from a geographically localized discharge For example
a smokestack represents an atmospheric pointsource and a sewage treatment plant
represents an aquatic pointsource
bull Non-pointsource - Pollution from a geographically distributed discharge For ex-
ample land application of fertilizers is a non-pointsource discharge of nitrogen and
other nutrients
Managing Agricultural Water Impacts 3
bull Effluent - Any pollution-containing discharge of water from an engineered process
such as irrigation industrial production or municipal sewage treatment
bull Aquifer - A porous subterranean region saturated with groundwater
bull Surface water - Water available in streams rivers lakes and reservoirs
bull Best management practices (BMPs) - Ways in which agricultural production
methods can be altered to minimize negative water impacts
13 Problem Statement
Agricultural operations including animal and crop farming are important contributors to
the depletion of water resource quality and quantity in the United States Agriculture
represents approximately 40 of total US water demand and irrigation is the largest
consumptive water use Agricultural operations have been identified by the Environmental
Protection Agency as the leading source of water quality impairment to rivers and lakes
While reliable quantification of specific water quality and quantity impacts is gener-
ally unavailable the water resource research community agrees that the following crucial
problems are directly relevant to agriculture
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater overpumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
4 Managing Agricultural Water Impacts
bull Present United States water policies are insufficient to ensure future water supply
security
This technology assessment explores the options available to the federal government to
effect a move toward sustainable agricultural water management in light of the problems
listed above
14 Stakeholders
Because water is necessary for life all living things are stakeholders in this technology
assessment in the broadest possible sense For the purposes of this report stakeholders
are classified into groups that can be expected to share similar goals regarding agricultural
water resource policies The rights-holders most directly affected by the issues examined in
this report are
bull Agricultural producers and related industries - Farmers and the industries who
supply farm-related products are primary stakeholders Producers directly influence
water resources through agricultural withdrawal use and discharge
bull Municipal water users - The second-largest water demand after agriculture is mu-
nicipalities Clean drinking water is distributed to residences as well as industrial
operations Municipalities often compete directly with agriculture in water-scarce
regions
bull Federal state and local government - Water resources are managed by a variety
of governmental agencies Because water is a resource crucial to national security the
government is a central stakeholder Laws respecting water are passed at all levels of
government with corresponding jurisdictions of enforcement
bull Indigenous groups - Treaty agreements allocate water rights to indigenous groups
across the country In some regions these stakeholders have been under pressure from
agriculture and municipalities to relinquish their claims
Managing Agricultural Water Impacts 5
bull Environmental advocacy groups - Water quality and quantity issues related to
agriculture have wide-ranging impacts on the environment Individuals seeking to
protect the environment constitute a stakeholder group that regularly participates in
the formulation of US policy
bull US trade partners - As an importer and exporter of products on the world market
changes in the cost or quantity of production of agricultural goods in the United States
will affect other nations
15 Problem Categories
The problems associated with agricultural water use are arranged in this technology as-
sessment in terms of the water cycle of the United States This water cycle begins with
a source proceeds to a use and terminates with a discharge After providing background
and context for the broad range of agricultural water problems the report details some es-
pecially important first-order and higher-order impacts which result from current national
policies and practices The selected impacts focus on the withdrawal of groundwater and
the diversion of surface water for agricultural use
16 Technology Tools
Chapter 4 offers a study of the technologies available for increasing the quantity of water
available increasing the efficiency of use and limiting the impacts of agricultural pollution
The state of the art in agricultural technology is presented in order to provide background
for technology-based policy recommendations Ultimately most of the policies offered by
this technology assessment are not technology-focused since broader structural changes in
agricultural production are found to be needed to bring about water resource sustainability
6 Managing Agricultural Water Impacts
17 Priority Policy Options
This technology assessment concludes with an examination of eleven priority policy options
available to the Congress to help bring about sustainable water management in the United
States The policy options are called ldquopriorityrdquo because they are identified as those most
likely to be highly effective or cost-efficient in acheiving national water resource sustainabil-
ity These policies were developed through a synthesis of the information presented in the
following chapters along with an understanding of the type of policy tools available to the
Congress The priority policy option are analyzed in terms of their anticipated first-order
and higher-order policy impacts
Chapter 2
Problem Background
To establish agricultural water management as a priority subject for national policy atten-
tion this report first examines the historical context present situation and quantitative
significance of selected water resource problems in the United States This chapter is orga-
nized by following the mass flow of water from source to use to discharge
bull SourcesmdashSurface water and groundwater the two most significant water sources
for agriculture are described along with national usage trends and implications for
specific regions of the country
bull UsesmdashIrrigation the primary use of water withdrawn for agricultural production is
quantified and the potential for increases in efficiency is discussed
bull DischargesmdashThe fate of agricultural water supplies is examined with regard to quan-
tity loss and pollution contributions
Before an analysis of these areas it is important to understand the degree to which a
national water balance can be quantified By understanding the difficulties involved with
modeling the water cycle and using this data to project future water trends policy makers
will be better prepared to appreciate and to act on the information contained in this report
7
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
iv Managing Agricultural Water Impacts
3 Selected Problem Impacts 23
31 Impacts of Groundwater Overdraft 23
311 Higher Pumping Costs 23
312 Land Subsidence 24
313 Depletion of Surface Water 25
314 Degraded Aquifer Water Quality 25
32 Impacts of Surface Water Diversion 26
321 Habitat Loss 26
322 Decreased Aquifer Recharge 26
323 Municipal Supply Problems 27
324 Pollution Concentration 27
33 Second-Order Impacts 27
331 Increasing Water Price 27
332 Loss of Farm Production 28
333 Changes to Animal Agriculture 28
334 Failure of Local Economies 28
4 Technologies 31
41 Water Sources Increasing Quantity 31
411 Desalination 31
412 Dams and Reservoirs 32
413 Water Reuse 33
42 Water Uses Improving Efficiency 36
421 Irrigation 37
422 Water-Thrifty Crops 40
43 Water Discharge Reducing Pollution 40
5 Priority Policy Options 43
51 Policy Tools 43
Managing Agricultural Water Impacts v
511 Regulatory Tools 44
512 Subsidy Tools 45
513 Informational Tools 46
52 Policy Options 46
521 Quality-Focused Policies 47
522 Quantity-Focused Policies 48
523 Comprehensive Policies 51
vi
List of Tables
21 The agricultural water cycle Inputs and outputs 8
22 Water consumption by food type 16
41 The typical costs of desalination 32
42 Irrigation methods 37
vii
viii
List of Figures
21 Estimated use of water in the United States 1950ndash1990 10
22 Aquifer locations in the western United States 11
23 1990 irrigation withdrawals as the percent of total freshwater withdrawals 14
24 US pesticide usage in 1997 20
31 Subsidence due to groundwater overdraft California 1925-1992 24
ix
x
Chapter 1
Executive Summary
ldquoWhen the well is dry we know the worth of waterrdquo
Benjamin Franklin Poor Richardrsquos Almanac 1746
ldquoWater is a very good servant but it is a cruel masterrdquo
CGD Roberts Adrift in America 1891
ldquoIf the wars of this century were fought over oil the wars of the next century will
be fought over watermdashunless we change our approach to managing this precious
and vital resourcerdquo
Ismail Serageldin Vice President of the World Bank 1995
11 Introduction
Today at the advent of a new millenium the United States has been forced to undertake a
critical reexamination of national security policies Water resource management although
not traditionally at the vanguard of such issues is increasingly recognized around the world
as a crucial aspect of national security While the United States does not presently top the
list of water-scarce countries an examination of the available data casts into question the
security of water resources in the future Water use trends in the United States indicate
1
2 Managing Agricultural Water Impacts
that the country will soon face a crisis in both water quality and water quantity unless
current policies and practices are amended
This problem-based technology assessment seeks to analyze the impacts of agricultural
water use in the United States and to propose solutions to effectively manage agricultural
water resources The goals of this assessment are as follows
1 Establish the problem as quantitatively as possible
2 Provide background and context for the problem aspects
3 Describe the direct and higher-order impacts of the problem
4 Examine the technologies available to solve the problem
5 Discuss the policy tools available to solve the problem
6 Predict the first and higher-order impacts of potential technology and policy solutions
12 Definitions
This technology assessment makes use of several terms and abbreviations In order to be
precise in the use of terms the following definitions are provided
bull Sustainability - Seeking to meet the needs of the present without compromising the
ability of future generations to meet their own needs
bull Pointsource - Pollution from a geographically localized discharge For example
a smokestack represents an atmospheric pointsource and a sewage treatment plant
represents an aquatic pointsource
bull Non-pointsource - Pollution from a geographically distributed discharge For ex-
ample land application of fertilizers is a non-pointsource discharge of nitrogen and
other nutrients
Managing Agricultural Water Impacts 3
bull Effluent - Any pollution-containing discharge of water from an engineered process
such as irrigation industrial production or municipal sewage treatment
bull Aquifer - A porous subterranean region saturated with groundwater
bull Surface water - Water available in streams rivers lakes and reservoirs
bull Best management practices (BMPs) - Ways in which agricultural production
methods can be altered to minimize negative water impacts
13 Problem Statement
Agricultural operations including animal and crop farming are important contributors to
the depletion of water resource quality and quantity in the United States Agriculture
represents approximately 40 of total US water demand and irrigation is the largest
consumptive water use Agricultural operations have been identified by the Environmental
Protection Agency as the leading source of water quality impairment to rivers and lakes
While reliable quantification of specific water quality and quantity impacts is gener-
ally unavailable the water resource research community agrees that the following crucial
problems are directly relevant to agriculture
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater overpumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
4 Managing Agricultural Water Impacts
bull Present United States water policies are insufficient to ensure future water supply
security
This technology assessment explores the options available to the federal government to
effect a move toward sustainable agricultural water management in light of the problems
listed above
14 Stakeholders
Because water is necessary for life all living things are stakeholders in this technology
assessment in the broadest possible sense For the purposes of this report stakeholders
are classified into groups that can be expected to share similar goals regarding agricultural
water resource policies The rights-holders most directly affected by the issues examined in
this report are
bull Agricultural producers and related industries - Farmers and the industries who
supply farm-related products are primary stakeholders Producers directly influence
water resources through agricultural withdrawal use and discharge
bull Municipal water users - The second-largest water demand after agriculture is mu-
nicipalities Clean drinking water is distributed to residences as well as industrial
operations Municipalities often compete directly with agriculture in water-scarce
regions
bull Federal state and local government - Water resources are managed by a variety
of governmental agencies Because water is a resource crucial to national security the
government is a central stakeholder Laws respecting water are passed at all levels of
government with corresponding jurisdictions of enforcement
bull Indigenous groups - Treaty agreements allocate water rights to indigenous groups
across the country In some regions these stakeholders have been under pressure from
agriculture and municipalities to relinquish their claims
Managing Agricultural Water Impacts 5
bull Environmental advocacy groups - Water quality and quantity issues related to
agriculture have wide-ranging impacts on the environment Individuals seeking to
protect the environment constitute a stakeholder group that regularly participates in
the formulation of US policy
bull US trade partners - As an importer and exporter of products on the world market
changes in the cost or quantity of production of agricultural goods in the United States
will affect other nations
15 Problem Categories
The problems associated with agricultural water use are arranged in this technology as-
sessment in terms of the water cycle of the United States This water cycle begins with
a source proceeds to a use and terminates with a discharge After providing background
and context for the broad range of agricultural water problems the report details some es-
pecially important first-order and higher-order impacts which result from current national
policies and practices The selected impacts focus on the withdrawal of groundwater and
the diversion of surface water for agricultural use
16 Technology Tools
Chapter 4 offers a study of the technologies available for increasing the quantity of water
available increasing the efficiency of use and limiting the impacts of agricultural pollution
The state of the art in agricultural technology is presented in order to provide background
for technology-based policy recommendations Ultimately most of the policies offered by
this technology assessment are not technology-focused since broader structural changes in
agricultural production are found to be needed to bring about water resource sustainability
6 Managing Agricultural Water Impacts
17 Priority Policy Options
This technology assessment concludes with an examination of eleven priority policy options
available to the Congress to help bring about sustainable water management in the United
States The policy options are called ldquopriorityrdquo because they are identified as those most
likely to be highly effective or cost-efficient in acheiving national water resource sustainabil-
ity These policies were developed through a synthesis of the information presented in the
following chapters along with an understanding of the type of policy tools available to the
Congress The priority policy option are analyzed in terms of their anticipated first-order
and higher-order policy impacts
Chapter 2
Problem Background
To establish agricultural water management as a priority subject for national policy atten-
tion this report first examines the historical context present situation and quantitative
significance of selected water resource problems in the United States This chapter is orga-
nized by following the mass flow of water from source to use to discharge
bull SourcesmdashSurface water and groundwater the two most significant water sources
for agriculture are described along with national usage trends and implications for
specific regions of the country
bull UsesmdashIrrigation the primary use of water withdrawn for agricultural production is
quantified and the potential for increases in efficiency is discussed
bull DischargesmdashThe fate of agricultural water supplies is examined with regard to quan-
tity loss and pollution contributions
Before an analysis of these areas it is important to understand the degree to which a
national water balance can be quantified By understanding the difficulties involved with
modeling the water cycle and using this data to project future water trends policy makers
will be better prepared to appreciate and to act on the information contained in this report
7
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts v
511 Regulatory Tools 44
512 Subsidy Tools 45
513 Informational Tools 46
52 Policy Options 46
521 Quality-Focused Policies 47
522 Quantity-Focused Policies 48
523 Comprehensive Policies 51
vi
List of Tables
21 The agricultural water cycle Inputs and outputs 8
22 Water consumption by food type 16
41 The typical costs of desalination 32
42 Irrigation methods 37
vii
viii
List of Figures
21 Estimated use of water in the United States 1950ndash1990 10
22 Aquifer locations in the western United States 11
23 1990 irrigation withdrawals as the percent of total freshwater withdrawals 14
24 US pesticide usage in 1997 20
31 Subsidence due to groundwater overdraft California 1925-1992 24
ix
x
Chapter 1
Executive Summary
ldquoWhen the well is dry we know the worth of waterrdquo
Benjamin Franklin Poor Richardrsquos Almanac 1746
ldquoWater is a very good servant but it is a cruel masterrdquo
CGD Roberts Adrift in America 1891
ldquoIf the wars of this century were fought over oil the wars of the next century will
be fought over watermdashunless we change our approach to managing this precious
and vital resourcerdquo
Ismail Serageldin Vice President of the World Bank 1995
11 Introduction
Today at the advent of a new millenium the United States has been forced to undertake a
critical reexamination of national security policies Water resource management although
not traditionally at the vanguard of such issues is increasingly recognized around the world
as a crucial aspect of national security While the United States does not presently top the
list of water-scarce countries an examination of the available data casts into question the
security of water resources in the future Water use trends in the United States indicate
1
2 Managing Agricultural Water Impacts
that the country will soon face a crisis in both water quality and water quantity unless
current policies and practices are amended
This problem-based technology assessment seeks to analyze the impacts of agricultural
water use in the United States and to propose solutions to effectively manage agricultural
water resources The goals of this assessment are as follows
1 Establish the problem as quantitatively as possible
2 Provide background and context for the problem aspects
3 Describe the direct and higher-order impacts of the problem
4 Examine the technologies available to solve the problem
5 Discuss the policy tools available to solve the problem
6 Predict the first and higher-order impacts of potential technology and policy solutions
12 Definitions
This technology assessment makes use of several terms and abbreviations In order to be
precise in the use of terms the following definitions are provided
bull Sustainability - Seeking to meet the needs of the present without compromising the
ability of future generations to meet their own needs
bull Pointsource - Pollution from a geographically localized discharge For example
a smokestack represents an atmospheric pointsource and a sewage treatment plant
represents an aquatic pointsource
bull Non-pointsource - Pollution from a geographically distributed discharge For ex-
ample land application of fertilizers is a non-pointsource discharge of nitrogen and
other nutrients
Managing Agricultural Water Impacts 3
bull Effluent - Any pollution-containing discharge of water from an engineered process
such as irrigation industrial production or municipal sewage treatment
bull Aquifer - A porous subterranean region saturated with groundwater
bull Surface water - Water available in streams rivers lakes and reservoirs
bull Best management practices (BMPs) - Ways in which agricultural production
methods can be altered to minimize negative water impacts
13 Problem Statement
Agricultural operations including animal and crop farming are important contributors to
the depletion of water resource quality and quantity in the United States Agriculture
represents approximately 40 of total US water demand and irrigation is the largest
consumptive water use Agricultural operations have been identified by the Environmental
Protection Agency as the leading source of water quality impairment to rivers and lakes
While reliable quantification of specific water quality and quantity impacts is gener-
ally unavailable the water resource research community agrees that the following crucial
problems are directly relevant to agriculture
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater overpumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
4 Managing Agricultural Water Impacts
bull Present United States water policies are insufficient to ensure future water supply
security
This technology assessment explores the options available to the federal government to
effect a move toward sustainable agricultural water management in light of the problems
listed above
14 Stakeholders
Because water is necessary for life all living things are stakeholders in this technology
assessment in the broadest possible sense For the purposes of this report stakeholders
are classified into groups that can be expected to share similar goals regarding agricultural
water resource policies The rights-holders most directly affected by the issues examined in
this report are
bull Agricultural producers and related industries - Farmers and the industries who
supply farm-related products are primary stakeholders Producers directly influence
water resources through agricultural withdrawal use and discharge
bull Municipal water users - The second-largest water demand after agriculture is mu-
nicipalities Clean drinking water is distributed to residences as well as industrial
operations Municipalities often compete directly with agriculture in water-scarce
regions
bull Federal state and local government - Water resources are managed by a variety
of governmental agencies Because water is a resource crucial to national security the
government is a central stakeholder Laws respecting water are passed at all levels of
government with corresponding jurisdictions of enforcement
bull Indigenous groups - Treaty agreements allocate water rights to indigenous groups
across the country In some regions these stakeholders have been under pressure from
agriculture and municipalities to relinquish their claims
Managing Agricultural Water Impacts 5
bull Environmental advocacy groups - Water quality and quantity issues related to
agriculture have wide-ranging impacts on the environment Individuals seeking to
protect the environment constitute a stakeholder group that regularly participates in
the formulation of US policy
bull US trade partners - As an importer and exporter of products on the world market
changes in the cost or quantity of production of agricultural goods in the United States
will affect other nations
15 Problem Categories
The problems associated with agricultural water use are arranged in this technology as-
sessment in terms of the water cycle of the United States This water cycle begins with
a source proceeds to a use and terminates with a discharge After providing background
and context for the broad range of agricultural water problems the report details some es-
pecially important first-order and higher-order impacts which result from current national
policies and practices The selected impacts focus on the withdrawal of groundwater and
the diversion of surface water for agricultural use
16 Technology Tools
Chapter 4 offers a study of the technologies available for increasing the quantity of water
available increasing the efficiency of use and limiting the impacts of agricultural pollution
The state of the art in agricultural technology is presented in order to provide background
for technology-based policy recommendations Ultimately most of the policies offered by
this technology assessment are not technology-focused since broader structural changes in
agricultural production are found to be needed to bring about water resource sustainability
6 Managing Agricultural Water Impacts
17 Priority Policy Options
This technology assessment concludes with an examination of eleven priority policy options
available to the Congress to help bring about sustainable water management in the United
States The policy options are called ldquopriorityrdquo because they are identified as those most
likely to be highly effective or cost-efficient in acheiving national water resource sustainabil-
ity These policies were developed through a synthesis of the information presented in the
following chapters along with an understanding of the type of policy tools available to the
Congress The priority policy option are analyzed in terms of their anticipated first-order
and higher-order policy impacts
Chapter 2
Problem Background
To establish agricultural water management as a priority subject for national policy atten-
tion this report first examines the historical context present situation and quantitative
significance of selected water resource problems in the United States This chapter is orga-
nized by following the mass flow of water from source to use to discharge
bull SourcesmdashSurface water and groundwater the two most significant water sources
for agriculture are described along with national usage trends and implications for
specific regions of the country
bull UsesmdashIrrigation the primary use of water withdrawn for agricultural production is
quantified and the potential for increases in efficiency is discussed
bull DischargesmdashThe fate of agricultural water supplies is examined with regard to quan-
tity loss and pollution contributions
Before an analysis of these areas it is important to understand the degree to which a
national water balance can be quantified By understanding the difficulties involved with
modeling the water cycle and using this data to project future water trends policy makers
will be better prepared to appreciate and to act on the information contained in this report
7
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
vi
List of Tables
21 The agricultural water cycle Inputs and outputs 8
22 Water consumption by food type 16
41 The typical costs of desalination 32
42 Irrigation methods 37
vii
viii
List of Figures
21 Estimated use of water in the United States 1950ndash1990 10
22 Aquifer locations in the western United States 11
23 1990 irrigation withdrawals as the percent of total freshwater withdrawals 14
24 US pesticide usage in 1997 20
31 Subsidence due to groundwater overdraft California 1925-1992 24
ix
x
Chapter 1
Executive Summary
ldquoWhen the well is dry we know the worth of waterrdquo
Benjamin Franklin Poor Richardrsquos Almanac 1746
ldquoWater is a very good servant but it is a cruel masterrdquo
CGD Roberts Adrift in America 1891
ldquoIf the wars of this century were fought over oil the wars of the next century will
be fought over watermdashunless we change our approach to managing this precious
and vital resourcerdquo
Ismail Serageldin Vice President of the World Bank 1995
11 Introduction
Today at the advent of a new millenium the United States has been forced to undertake a
critical reexamination of national security policies Water resource management although
not traditionally at the vanguard of such issues is increasingly recognized around the world
as a crucial aspect of national security While the United States does not presently top the
list of water-scarce countries an examination of the available data casts into question the
security of water resources in the future Water use trends in the United States indicate
1
2 Managing Agricultural Water Impacts
that the country will soon face a crisis in both water quality and water quantity unless
current policies and practices are amended
This problem-based technology assessment seeks to analyze the impacts of agricultural
water use in the United States and to propose solutions to effectively manage agricultural
water resources The goals of this assessment are as follows
1 Establish the problem as quantitatively as possible
2 Provide background and context for the problem aspects
3 Describe the direct and higher-order impacts of the problem
4 Examine the technologies available to solve the problem
5 Discuss the policy tools available to solve the problem
6 Predict the first and higher-order impacts of potential technology and policy solutions
12 Definitions
This technology assessment makes use of several terms and abbreviations In order to be
precise in the use of terms the following definitions are provided
bull Sustainability - Seeking to meet the needs of the present without compromising the
ability of future generations to meet their own needs
bull Pointsource - Pollution from a geographically localized discharge For example
a smokestack represents an atmospheric pointsource and a sewage treatment plant
represents an aquatic pointsource
bull Non-pointsource - Pollution from a geographically distributed discharge For ex-
ample land application of fertilizers is a non-pointsource discharge of nitrogen and
other nutrients
Managing Agricultural Water Impacts 3
bull Effluent - Any pollution-containing discharge of water from an engineered process
such as irrigation industrial production or municipal sewage treatment
bull Aquifer - A porous subterranean region saturated with groundwater
bull Surface water - Water available in streams rivers lakes and reservoirs
bull Best management practices (BMPs) - Ways in which agricultural production
methods can be altered to minimize negative water impacts
13 Problem Statement
Agricultural operations including animal and crop farming are important contributors to
the depletion of water resource quality and quantity in the United States Agriculture
represents approximately 40 of total US water demand and irrigation is the largest
consumptive water use Agricultural operations have been identified by the Environmental
Protection Agency as the leading source of water quality impairment to rivers and lakes
While reliable quantification of specific water quality and quantity impacts is gener-
ally unavailable the water resource research community agrees that the following crucial
problems are directly relevant to agriculture
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater overpumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
4 Managing Agricultural Water Impacts
bull Present United States water policies are insufficient to ensure future water supply
security
This technology assessment explores the options available to the federal government to
effect a move toward sustainable agricultural water management in light of the problems
listed above
14 Stakeholders
Because water is necessary for life all living things are stakeholders in this technology
assessment in the broadest possible sense For the purposes of this report stakeholders
are classified into groups that can be expected to share similar goals regarding agricultural
water resource policies The rights-holders most directly affected by the issues examined in
this report are
bull Agricultural producers and related industries - Farmers and the industries who
supply farm-related products are primary stakeholders Producers directly influence
water resources through agricultural withdrawal use and discharge
bull Municipal water users - The second-largest water demand after agriculture is mu-
nicipalities Clean drinking water is distributed to residences as well as industrial
operations Municipalities often compete directly with agriculture in water-scarce
regions
bull Federal state and local government - Water resources are managed by a variety
of governmental agencies Because water is a resource crucial to national security the
government is a central stakeholder Laws respecting water are passed at all levels of
government with corresponding jurisdictions of enforcement
bull Indigenous groups - Treaty agreements allocate water rights to indigenous groups
across the country In some regions these stakeholders have been under pressure from
agriculture and municipalities to relinquish their claims
Managing Agricultural Water Impacts 5
bull Environmental advocacy groups - Water quality and quantity issues related to
agriculture have wide-ranging impacts on the environment Individuals seeking to
protect the environment constitute a stakeholder group that regularly participates in
the formulation of US policy
bull US trade partners - As an importer and exporter of products on the world market
changes in the cost or quantity of production of agricultural goods in the United States
will affect other nations
15 Problem Categories
The problems associated with agricultural water use are arranged in this technology as-
sessment in terms of the water cycle of the United States This water cycle begins with
a source proceeds to a use and terminates with a discharge After providing background
and context for the broad range of agricultural water problems the report details some es-
pecially important first-order and higher-order impacts which result from current national
policies and practices The selected impacts focus on the withdrawal of groundwater and
the diversion of surface water for agricultural use
16 Technology Tools
Chapter 4 offers a study of the technologies available for increasing the quantity of water
available increasing the efficiency of use and limiting the impacts of agricultural pollution
The state of the art in agricultural technology is presented in order to provide background
for technology-based policy recommendations Ultimately most of the policies offered by
this technology assessment are not technology-focused since broader structural changes in
agricultural production are found to be needed to bring about water resource sustainability
6 Managing Agricultural Water Impacts
17 Priority Policy Options
This technology assessment concludes with an examination of eleven priority policy options
available to the Congress to help bring about sustainable water management in the United
States The policy options are called ldquopriorityrdquo because they are identified as those most
likely to be highly effective or cost-efficient in acheiving national water resource sustainabil-
ity These policies were developed through a synthesis of the information presented in the
following chapters along with an understanding of the type of policy tools available to the
Congress The priority policy option are analyzed in terms of their anticipated first-order
and higher-order policy impacts
Chapter 2
Problem Background
To establish agricultural water management as a priority subject for national policy atten-
tion this report first examines the historical context present situation and quantitative
significance of selected water resource problems in the United States This chapter is orga-
nized by following the mass flow of water from source to use to discharge
bull SourcesmdashSurface water and groundwater the two most significant water sources
for agriculture are described along with national usage trends and implications for
specific regions of the country
bull UsesmdashIrrigation the primary use of water withdrawn for agricultural production is
quantified and the potential for increases in efficiency is discussed
bull DischargesmdashThe fate of agricultural water supplies is examined with regard to quan-
tity loss and pollution contributions
Before an analysis of these areas it is important to understand the degree to which a
national water balance can be quantified By understanding the difficulties involved with
modeling the water cycle and using this data to project future water trends policy makers
will be better prepared to appreciate and to act on the information contained in this report
7
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
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Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
List of Tables
21 The agricultural water cycle Inputs and outputs 8
22 Water consumption by food type 16
41 The typical costs of desalination 32
42 Irrigation methods 37
vii
viii
List of Figures
21 Estimated use of water in the United States 1950ndash1990 10
22 Aquifer locations in the western United States 11
23 1990 irrigation withdrawals as the percent of total freshwater withdrawals 14
24 US pesticide usage in 1997 20
31 Subsidence due to groundwater overdraft California 1925-1992 24
ix
x
Chapter 1
Executive Summary
ldquoWhen the well is dry we know the worth of waterrdquo
Benjamin Franklin Poor Richardrsquos Almanac 1746
ldquoWater is a very good servant but it is a cruel masterrdquo
CGD Roberts Adrift in America 1891
ldquoIf the wars of this century were fought over oil the wars of the next century will
be fought over watermdashunless we change our approach to managing this precious
and vital resourcerdquo
Ismail Serageldin Vice President of the World Bank 1995
11 Introduction
Today at the advent of a new millenium the United States has been forced to undertake a
critical reexamination of national security policies Water resource management although
not traditionally at the vanguard of such issues is increasingly recognized around the world
as a crucial aspect of national security While the United States does not presently top the
list of water-scarce countries an examination of the available data casts into question the
security of water resources in the future Water use trends in the United States indicate
1
2 Managing Agricultural Water Impacts
that the country will soon face a crisis in both water quality and water quantity unless
current policies and practices are amended
This problem-based technology assessment seeks to analyze the impacts of agricultural
water use in the United States and to propose solutions to effectively manage agricultural
water resources The goals of this assessment are as follows
1 Establish the problem as quantitatively as possible
2 Provide background and context for the problem aspects
3 Describe the direct and higher-order impacts of the problem
4 Examine the technologies available to solve the problem
5 Discuss the policy tools available to solve the problem
6 Predict the first and higher-order impacts of potential technology and policy solutions
12 Definitions
This technology assessment makes use of several terms and abbreviations In order to be
precise in the use of terms the following definitions are provided
bull Sustainability - Seeking to meet the needs of the present without compromising the
ability of future generations to meet their own needs
bull Pointsource - Pollution from a geographically localized discharge For example
a smokestack represents an atmospheric pointsource and a sewage treatment plant
represents an aquatic pointsource
bull Non-pointsource - Pollution from a geographically distributed discharge For ex-
ample land application of fertilizers is a non-pointsource discharge of nitrogen and
other nutrients
Managing Agricultural Water Impacts 3
bull Effluent - Any pollution-containing discharge of water from an engineered process
such as irrigation industrial production or municipal sewage treatment
bull Aquifer - A porous subterranean region saturated with groundwater
bull Surface water - Water available in streams rivers lakes and reservoirs
bull Best management practices (BMPs) - Ways in which agricultural production
methods can be altered to minimize negative water impacts
13 Problem Statement
Agricultural operations including animal and crop farming are important contributors to
the depletion of water resource quality and quantity in the United States Agriculture
represents approximately 40 of total US water demand and irrigation is the largest
consumptive water use Agricultural operations have been identified by the Environmental
Protection Agency as the leading source of water quality impairment to rivers and lakes
While reliable quantification of specific water quality and quantity impacts is gener-
ally unavailable the water resource research community agrees that the following crucial
problems are directly relevant to agriculture
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater overpumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
4 Managing Agricultural Water Impacts
bull Present United States water policies are insufficient to ensure future water supply
security
This technology assessment explores the options available to the federal government to
effect a move toward sustainable agricultural water management in light of the problems
listed above
14 Stakeholders
Because water is necessary for life all living things are stakeholders in this technology
assessment in the broadest possible sense For the purposes of this report stakeholders
are classified into groups that can be expected to share similar goals regarding agricultural
water resource policies The rights-holders most directly affected by the issues examined in
this report are
bull Agricultural producers and related industries - Farmers and the industries who
supply farm-related products are primary stakeholders Producers directly influence
water resources through agricultural withdrawal use and discharge
bull Municipal water users - The second-largest water demand after agriculture is mu-
nicipalities Clean drinking water is distributed to residences as well as industrial
operations Municipalities often compete directly with agriculture in water-scarce
regions
bull Federal state and local government - Water resources are managed by a variety
of governmental agencies Because water is a resource crucial to national security the
government is a central stakeholder Laws respecting water are passed at all levels of
government with corresponding jurisdictions of enforcement
bull Indigenous groups - Treaty agreements allocate water rights to indigenous groups
across the country In some regions these stakeholders have been under pressure from
agriculture and municipalities to relinquish their claims
Managing Agricultural Water Impacts 5
bull Environmental advocacy groups - Water quality and quantity issues related to
agriculture have wide-ranging impacts on the environment Individuals seeking to
protect the environment constitute a stakeholder group that regularly participates in
the formulation of US policy
bull US trade partners - As an importer and exporter of products on the world market
changes in the cost or quantity of production of agricultural goods in the United States
will affect other nations
15 Problem Categories
The problems associated with agricultural water use are arranged in this technology as-
sessment in terms of the water cycle of the United States This water cycle begins with
a source proceeds to a use and terminates with a discharge After providing background
and context for the broad range of agricultural water problems the report details some es-
pecially important first-order and higher-order impacts which result from current national
policies and practices The selected impacts focus on the withdrawal of groundwater and
the diversion of surface water for agricultural use
16 Technology Tools
Chapter 4 offers a study of the technologies available for increasing the quantity of water
available increasing the efficiency of use and limiting the impacts of agricultural pollution
The state of the art in agricultural technology is presented in order to provide background
for technology-based policy recommendations Ultimately most of the policies offered by
this technology assessment are not technology-focused since broader structural changes in
agricultural production are found to be needed to bring about water resource sustainability
6 Managing Agricultural Water Impacts
17 Priority Policy Options
This technology assessment concludes with an examination of eleven priority policy options
available to the Congress to help bring about sustainable water management in the United
States The policy options are called ldquopriorityrdquo because they are identified as those most
likely to be highly effective or cost-efficient in acheiving national water resource sustainabil-
ity These policies were developed through a synthesis of the information presented in the
following chapters along with an understanding of the type of policy tools available to the
Congress The priority policy option are analyzed in terms of their anticipated first-order
and higher-order policy impacts
Chapter 2
Problem Background
To establish agricultural water management as a priority subject for national policy atten-
tion this report first examines the historical context present situation and quantitative
significance of selected water resource problems in the United States This chapter is orga-
nized by following the mass flow of water from source to use to discharge
bull SourcesmdashSurface water and groundwater the two most significant water sources
for agriculture are described along with national usage trends and implications for
specific regions of the country
bull UsesmdashIrrigation the primary use of water withdrawn for agricultural production is
quantified and the potential for increases in efficiency is discussed
bull DischargesmdashThe fate of agricultural water supplies is examined with regard to quan-
tity loss and pollution contributions
Before an analysis of these areas it is important to understand the degree to which a
national water balance can be quantified By understanding the difficulties involved with
modeling the water cycle and using this data to project future water trends policy makers
will be better prepared to appreciate and to act on the information contained in this report
7
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
viii
List of Figures
21 Estimated use of water in the United States 1950ndash1990 10
22 Aquifer locations in the western United States 11
23 1990 irrigation withdrawals as the percent of total freshwater withdrawals 14
24 US pesticide usage in 1997 20
31 Subsidence due to groundwater overdraft California 1925-1992 24
ix
x
Chapter 1
Executive Summary
ldquoWhen the well is dry we know the worth of waterrdquo
Benjamin Franklin Poor Richardrsquos Almanac 1746
ldquoWater is a very good servant but it is a cruel masterrdquo
CGD Roberts Adrift in America 1891
ldquoIf the wars of this century were fought over oil the wars of the next century will
be fought over watermdashunless we change our approach to managing this precious
and vital resourcerdquo
Ismail Serageldin Vice President of the World Bank 1995
11 Introduction
Today at the advent of a new millenium the United States has been forced to undertake a
critical reexamination of national security policies Water resource management although
not traditionally at the vanguard of such issues is increasingly recognized around the world
as a crucial aspect of national security While the United States does not presently top the
list of water-scarce countries an examination of the available data casts into question the
security of water resources in the future Water use trends in the United States indicate
1
2 Managing Agricultural Water Impacts
that the country will soon face a crisis in both water quality and water quantity unless
current policies and practices are amended
This problem-based technology assessment seeks to analyze the impacts of agricultural
water use in the United States and to propose solutions to effectively manage agricultural
water resources The goals of this assessment are as follows
1 Establish the problem as quantitatively as possible
2 Provide background and context for the problem aspects
3 Describe the direct and higher-order impacts of the problem
4 Examine the technologies available to solve the problem
5 Discuss the policy tools available to solve the problem
6 Predict the first and higher-order impacts of potential technology and policy solutions
12 Definitions
This technology assessment makes use of several terms and abbreviations In order to be
precise in the use of terms the following definitions are provided
bull Sustainability - Seeking to meet the needs of the present without compromising the
ability of future generations to meet their own needs
bull Pointsource - Pollution from a geographically localized discharge For example
a smokestack represents an atmospheric pointsource and a sewage treatment plant
represents an aquatic pointsource
bull Non-pointsource - Pollution from a geographically distributed discharge For ex-
ample land application of fertilizers is a non-pointsource discharge of nitrogen and
other nutrients
Managing Agricultural Water Impacts 3
bull Effluent - Any pollution-containing discharge of water from an engineered process
such as irrigation industrial production or municipal sewage treatment
bull Aquifer - A porous subterranean region saturated with groundwater
bull Surface water - Water available in streams rivers lakes and reservoirs
bull Best management practices (BMPs) - Ways in which agricultural production
methods can be altered to minimize negative water impacts
13 Problem Statement
Agricultural operations including animal and crop farming are important contributors to
the depletion of water resource quality and quantity in the United States Agriculture
represents approximately 40 of total US water demand and irrigation is the largest
consumptive water use Agricultural operations have been identified by the Environmental
Protection Agency as the leading source of water quality impairment to rivers and lakes
While reliable quantification of specific water quality and quantity impacts is gener-
ally unavailable the water resource research community agrees that the following crucial
problems are directly relevant to agriculture
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater overpumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
4 Managing Agricultural Water Impacts
bull Present United States water policies are insufficient to ensure future water supply
security
This technology assessment explores the options available to the federal government to
effect a move toward sustainable agricultural water management in light of the problems
listed above
14 Stakeholders
Because water is necessary for life all living things are stakeholders in this technology
assessment in the broadest possible sense For the purposes of this report stakeholders
are classified into groups that can be expected to share similar goals regarding agricultural
water resource policies The rights-holders most directly affected by the issues examined in
this report are
bull Agricultural producers and related industries - Farmers and the industries who
supply farm-related products are primary stakeholders Producers directly influence
water resources through agricultural withdrawal use and discharge
bull Municipal water users - The second-largest water demand after agriculture is mu-
nicipalities Clean drinking water is distributed to residences as well as industrial
operations Municipalities often compete directly with agriculture in water-scarce
regions
bull Federal state and local government - Water resources are managed by a variety
of governmental agencies Because water is a resource crucial to national security the
government is a central stakeholder Laws respecting water are passed at all levels of
government with corresponding jurisdictions of enforcement
bull Indigenous groups - Treaty agreements allocate water rights to indigenous groups
across the country In some regions these stakeholders have been under pressure from
agriculture and municipalities to relinquish their claims
Managing Agricultural Water Impacts 5
bull Environmental advocacy groups - Water quality and quantity issues related to
agriculture have wide-ranging impacts on the environment Individuals seeking to
protect the environment constitute a stakeholder group that regularly participates in
the formulation of US policy
bull US trade partners - As an importer and exporter of products on the world market
changes in the cost or quantity of production of agricultural goods in the United States
will affect other nations
15 Problem Categories
The problems associated with agricultural water use are arranged in this technology as-
sessment in terms of the water cycle of the United States This water cycle begins with
a source proceeds to a use and terminates with a discharge After providing background
and context for the broad range of agricultural water problems the report details some es-
pecially important first-order and higher-order impacts which result from current national
policies and practices The selected impacts focus on the withdrawal of groundwater and
the diversion of surface water for agricultural use
16 Technology Tools
Chapter 4 offers a study of the technologies available for increasing the quantity of water
available increasing the efficiency of use and limiting the impacts of agricultural pollution
The state of the art in agricultural technology is presented in order to provide background
for technology-based policy recommendations Ultimately most of the policies offered by
this technology assessment are not technology-focused since broader structural changes in
agricultural production are found to be needed to bring about water resource sustainability
6 Managing Agricultural Water Impacts
17 Priority Policy Options
This technology assessment concludes with an examination of eleven priority policy options
available to the Congress to help bring about sustainable water management in the United
States The policy options are called ldquopriorityrdquo because they are identified as those most
likely to be highly effective or cost-efficient in acheiving national water resource sustainabil-
ity These policies were developed through a synthesis of the information presented in the
following chapters along with an understanding of the type of policy tools available to the
Congress The priority policy option are analyzed in terms of their anticipated first-order
and higher-order policy impacts
Chapter 2
Problem Background
To establish agricultural water management as a priority subject for national policy atten-
tion this report first examines the historical context present situation and quantitative
significance of selected water resource problems in the United States This chapter is orga-
nized by following the mass flow of water from source to use to discharge
bull SourcesmdashSurface water and groundwater the two most significant water sources
for agriculture are described along with national usage trends and implications for
specific regions of the country
bull UsesmdashIrrigation the primary use of water withdrawn for agricultural production is
quantified and the potential for increases in efficiency is discussed
bull DischargesmdashThe fate of agricultural water supplies is examined with regard to quan-
tity loss and pollution contributions
Before an analysis of these areas it is important to understand the degree to which a
national water balance can be quantified By understanding the difficulties involved with
modeling the water cycle and using this data to project future water trends policy makers
will be better prepared to appreciate and to act on the information contained in this report
7
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
List of Figures
21 Estimated use of water in the United States 1950ndash1990 10
22 Aquifer locations in the western United States 11
23 1990 irrigation withdrawals as the percent of total freshwater withdrawals 14
24 US pesticide usage in 1997 20
31 Subsidence due to groundwater overdraft California 1925-1992 24
ix
x
Chapter 1
Executive Summary
ldquoWhen the well is dry we know the worth of waterrdquo
Benjamin Franklin Poor Richardrsquos Almanac 1746
ldquoWater is a very good servant but it is a cruel masterrdquo
CGD Roberts Adrift in America 1891
ldquoIf the wars of this century were fought over oil the wars of the next century will
be fought over watermdashunless we change our approach to managing this precious
and vital resourcerdquo
Ismail Serageldin Vice President of the World Bank 1995
11 Introduction
Today at the advent of a new millenium the United States has been forced to undertake a
critical reexamination of national security policies Water resource management although
not traditionally at the vanguard of such issues is increasingly recognized around the world
as a crucial aspect of national security While the United States does not presently top the
list of water-scarce countries an examination of the available data casts into question the
security of water resources in the future Water use trends in the United States indicate
1
2 Managing Agricultural Water Impacts
that the country will soon face a crisis in both water quality and water quantity unless
current policies and practices are amended
This problem-based technology assessment seeks to analyze the impacts of agricultural
water use in the United States and to propose solutions to effectively manage agricultural
water resources The goals of this assessment are as follows
1 Establish the problem as quantitatively as possible
2 Provide background and context for the problem aspects
3 Describe the direct and higher-order impacts of the problem
4 Examine the technologies available to solve the problem
5 Discuss the policy tools available to solve the problem
6 Predict the first and higher-order impacts of potential technology and policy solutions
12 Definitions
This technology assessment makes use of several terms and abbreviations In order to be
precise in the use of terms the following definitions are provided
bull Sustainability - Seeking to meet the needs of the present without compromising the
ability of future generations to meet their own needs
bull Pointsource - Pollution from a geographically localized discharge For example
a smokestack represents an atmospheric pointsource and a sewage treatment plant
represents an aquatic pointsource
bull Non-pointsource - Pollution from a geographically distributed discharge For ex-
ample land application of fertilizers is a non-pointsource discharge of nitrogen and
other nutrients
Managing Agricultural Water Impacts 3
bull Effluent - Any pollution-containing discharge of water from an engineered process
such as irrigation industrial production or municipal sewage treatment
bull Aquifer - A porous subterranean region saturated with groundwater
bull Surface water - Water available in streams rivers lakes and reservoirs
bull Best management practices (BMPs) - Ways in which agricultural production
methods can be altered to minimize negative water impacts
13 Problem Statement
Agricultural operations including animal and crop farming are important contributors to
the depletion of water resource quality and quantity in the United States Agriculture
represents approximately 40 of total US water demand and irrigation is the largest
consumptive water use Agricultural operations have been identified by the Environmental
Protection Agency as the leading source of water quality impairment to rivers and lakes
While reliable quantification of specific water quality and quantity impacts is gener-
ally unavailable the water resource research community agrees that the following crucial
problems are directly relevant to agriculture
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater overpumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
4 Managing Agricultural Water Impacts
bull Present United States water policies are insufficient to ensure future water supply
security
This technology assessment explores the options available to the federal government to
effect a move toward sustainable agricultural water management in light of the problems
listed above
14 Stakeholders
Because water is necessary for life all living things are stakeholders in this technology
assessment in the broadest possible sense For the purposes of this report stakeholders
are classified into groups that can be expected to share similar goals regarding agricultural
water resource policies The rights-holders most directly affected by the issues examined in
this report are
bull Agricultural producers and related industries - Farmers and the industries who
supply farm-related products are primary stakeholders Producers directly influence
water resources through agricultural withdrawal use and discharge
bull Municipal water users - The second-largest water demand after agriculture is mu-
nicipalities Clean drinking water is distributed to residences as well as industrial
operations Municipalities often compete directly with agriculture in water-scarce
regions
bull Federal state and local government - Water resources are managed by a variety
of governmental agencies Because water is a resource crucial to national security the
government is a central stakeholder Laws respecting water are passed at all levels of
government with corresponding jurisdictions of enforcement
bull Indigenous groups - Treaty agreements allocate water rights to indigenous groups
across the country In some regions these stakeholders have been under pressure from
agriculture and municipalities to relinquish their claims
Managing Agricultural Water Impacts 5
bull Environmental advocacy groups - Water quality and quantity issues related to
agriculture have wide-ranging impacts on the environment Individuals seeking to
protect the environment constitute a stakeholder group that regularly participates in
the formulation of US policy
bull US trade partners - As an importer and exporter of products on the world market
changes in the cost or quantity of production of agricultural goods in the United States
will affect other nations
15 Problem Categories
The problems associated with agricultural water use are arranged in this technology as-
sessment in terms of the water cycle of the United States This water cycle begins with
a source proceeds to a use and terminates with a discharge After providing background
and context for the broad range of agricultural water problems the report details some es-
pecially important first-order and higher-order impacts which result from current national
policies and practices The selected impacts focus on the withdrawal of groundwater and
the diversion of surface water for agricultural use
16 Technology Tools
Chapter 4 offers a study of the technologies available for increasing the quantity of water
available increasing the efficiency of use and limiting the impacts of agricultural pollution
The state of the art in agricultural technology is presented in order to provide background
for technology-based policy recommendations Ultimately most of the policies offered by
this technology assessment are not technology-focused since broader structural changes in
agricultural production are found to be needed to bring about water resource sustainability
6 Managing Agricultural Water Impacts
17 Priority Policy Options
This technology assessment concludes with an examination of eleven priority policy options
available to the Congress to help bring about sustainable water management in the United
States The policy options are called ldquopriorityrdquo because they are identified as those most
likely to be highly effective or cost-efficient in acheiving national water resource sustainabil-
ity These policies were developed through a synthesis of the information presented in the
following chapters along with an understanding of the type of policy tools available to the
Congress The priority policy option are analyzed in terms of their anticipated first-order
and higher-order policy impacts
Chapter 2
Problem Background
To establish agricultural water management as a priority subject for national policy atten-
tion this report first examines the historical context present situation and quantitative
significance of selected water resource problems in the United States This chapter is orga-
nized by following the mass flow of water from source to use to discharge
bull SourcesmdashSurface water and groundwater the two most significant water sources
for agriculture are described along with national usage trends and implications for
specific regions of the country
bull UsesmdashIrrigation the primary use of water withdrawn for agricultural production is
quantified and the potential for increases in efficiency is discussed
bull DischargesmdashThe fate of agricultural water supplies is examined with regard to quan-
tity loss and pollution contributions
Before an analysis of these areas it is important to understand the degree to which a
national water balance can be quantified By understanding the difficulties involved with
modeling the water cycle and using this data to project future water trends policy makers
will be better prepared to appreciate and to act on the information contained in this report
7
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
x
Chapter 1
Executive Summary
ldquoWhen the well is dry we know the worth of waterrdquo
Benjamin Franklin Poor Richardrsquos Almanac 1746
ldquoWater is a very good servant but it is a cruel masterrdquo
CGD Roberts Adrift in America 1891
ldquoIf the wars of this century were fought over oil the wars of the next century will
be fought over watermdashunless we change our approach to managing this precious
and vital resourcerdquo
Ismail Serageldin Vice President of the World Bank 1995
11 Introduction
Today at the advent of a new millenium the United States has been forced to undertake a
critical reexamination of national security policies Water resource management although
not traditionally at the vanguard of such issues is increasingly recognized around the world
as a crucial aspect of national security While the United States does not presently top the
list of water-scarce countries an examination of the available data casts into question the
security of water resources in the future Water use trends in the United States indicate
1
2 Managing Agricultural Water Impacts
that the country will soon face a crisis in both water quality and water quantity unless
current policies and practices are amended
This problem-based technology assessment seeks to analyze the impacts of agricultural
water use in the United States and to propose solutions to effectively manage agricultural
water resources The goals of this assessment are as follows
1 Establish the problem as quantitatively as possible
2 Provide background and context for the problem aspects
3 Describe the direct and higher-order impacts of the problem
4 Examine the technologies available to solve the problem
5 Discuss the policy tools available to solve the problem
6 Predict the first and higher-order impacts of potential technology and policy solutions
12 Definitions
This technology assessment makes use of several terms and abbreviations In order to be
precise in the use of terms the following definitions are provided
bull Sustainability - Seeking to meet the needs of the present without compromising the
ability of future generations to meet their own needs
bull Pointsource - Pollution from a geographically localized discharge For example
a smokestack represents an atmospheric pointsource and a sewage treatment plant
represents an aquatic pointsource
bull Non-pointsource - Pollution from a geographically distributed discharge For ex-
ample land application of fertilizers is a non-pointsource discharge of nitrogen and
other nutrients
Managing Agricultural Water Impacts 3
bull Effluent - Any pollution-containing discharge of water from an engineered process
such as irrigation industrial production or municipal sewage treatment
bull Aquifer - A porous subterranean region saturated with groundwater
bull Surface water - Water available in streams rivers lakes and reservoirs
bull Best management practices (BMPs) - Ways in which agricultural production
methods can be altered to minimize negative water impacts
13 Problem Statement
Agricultural operations including animal and crop farming are important contributors to
the depletion of water resource quality and quantity in the United States Agriculture
represents approximately 40 of total US water demand and irrigation is the largest
consumptive water use Agricultural operations have been identified by the Environmental
Protection Agency as the leading source of water quality impairment to rivers and lakes
While reliable quantification of specific water quality and quantity impacts is gener-
ally unavailable the water resource research community agrees that the following crucial
problems are directly relevant to agriculture
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater overpumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
4 Managing Agricultural Water Impacts
bull Present United States water policies are insufficient to ensure future water supply
security
This technology assessment explores the options available to the federal government to
effect a move toward sustainable agricultural water management in light of the problems
listed above
14 Stakeholders
Because water is necessary for life all living things are stakeholders in this technology
assessment in the broadest possible sense For the purposes of this report stakeholders
are classified into groups that can be expected to share similar goals regarding agricultural
water resource policies The rights-holders most directly affected by the issues examined in
this report are
bull Agricultural producers and related industries - Farmers and the industries who
supply farm-related products are primary stakeholders Producers directly influence
water resources through agricultural withdrawal use and discharge
bull Municipal water users - The second-largest water demand after agriculture is mu-
nicipalities Clean drinking water is distributed to residences as well as industrial
operations Municipalities often compete directly with agriculture in water-scarce
regions
bull Federal state and local government - Water resources are managed by a variety
of governmental agencies Because water is a resource crucial to national security the
government is a central stakeholder Laws respecting water are passed at all levels of
government with corresponding jurisdictions of enforcement
bull Indigenous groups - Treaty agreements allocate water rights to indigenous groups
across the country In some regions these stakeholders have been under pressure from
agriculture and municipalities to relinquish their claims
Managing Agricultural Water Impacts 5
bull Environmental advocacy groups - Water quality and quantity issues related to
agriculture have wide-ranging impacts on the environment Individuals seeking to
protect the environment constitute a stakeholder group that regularly participates in
the formulation of US policy
bull US trade partners - As an importer and exporter of products on the world market
changes in the cost or quantity of production of agricultural goods in the United States
will affect other nations
15 Problem Categories
The problems associated with agricultural water use are arranged in this technology as-
sessment in terms of the water cycle of the United States This water cycle begins with
a source proceeds to a use and terminates with a discharge After providing background
and context for the broad range of agricultural water problems the report details some es-
pecially important first-order and higher-order impacts which result from current national
policies and practices The selected impacts focus on the withdrawal of groundwater and
the diversion of surface water for agricultural use
16 Technology Tools
Chapter 4 offers a study of the technologies available for increasing the quantity of water
available increasing the efficiency of use and limiting the impacts of agricultural pollution
The state of the art in agricultural technology is presented in order to provide background
for technology-based policy recommendations Ultimately most of the policies offered by
this technology assessment are not technology-focused since broader structural changes in
agricultural production are found to be needed to bring about water resource sustainability
6 Managing Agricultural Water Impacts
17 Priority Policy Options
This technology assessment concludes with an examination of eleven priority policy options
available to the Congress to help bring about sustainable water management in the United
States The policy options are called ldquopriorityrdquo because they are identified as those most
likely to be highly effective or cost-efficient in acheiving national water resource sustainabil-
ity These policies were developed through a synthesis of the information presented in the
following chapters along with an understanding of the type of policy tools available to the
Congress The priority policy option are analyzed in terms of their anticipated first-order
and higher-order policy impacts
Chapter 2
Problem Background
To establish agricultural water management as a priority subject for national policy atten-
tion this report first examines the historical context present situation and quantitative
significance of selected water resource problems in the United States This chapter is orga-
nized by following the mass flow of water from source to use to discharge
bull SourcesmdashSurface water and groundwater the two most significant water sources
for agriculture are described along with national usage trends and implications for
specific regions of the country
bull UsesmdashIrrigation the primary use of water withdrawn for agricultural production is
quantified and the potential for increases in efficiency is discussed
bull DischargesmdashThe fate of agricultural water supplies is examined with regard to quan-
tity loss and pollution contributions
Before an analysis of these areas it is important to understand the degree to which a
national water balance can be quantified By understanding the difficulties involved with
modeling the water cycle and using this data to project future water trends policy makers
will be better prepared to appreciate and to act on the information contained in this report
7
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Chapter 1
Executive Summary
ldquoWhen the well is dry we know the worth of waterrdquo
Benjamin Franklin Poor Richardrsquos Almanac 1746
ldquoWater is a very good servant but it is a cruel masterrdquo
CGD Roberts Adrift in America 1891
ldquoIf the wars of this century were fought over oil the wars of the next century will
be fought over watermdashunless we change our approach to managing this precious
and vital resourcerdquo
Ismail Serageldin Vice President of the World Bank 1995
11 Introduction
Today at the advent of a new millenium the United States has been forced to undertake a
critical reexamination of national security policies Water resource management although
not traditionally at the vanguard of such issues is increasingly recognized around the world
as a crucial aspect of national security While the United States does not presently top the
list of water-scarce countries an examination of the available data casts into question the
security of water resources in the future Water use trends in the United States indicate
1
2 Managing Agricultural Water Impacts
that the country will soon face a crisis in both water quality and water quantity unless
current policies and practices are amended
This problem-based technology assessment seeks to analyze the impacts of agricultural
water use in the United States and to propose solutions to effectively manage agricultural
water resources The goals of this assessment are as follows
1 Establish the problem as quantitatively as possible
2 Provide background and context for the problem aspects
3 Describe the direct and higher-order impacts of the problem
4 Examine the technologies available to solve the problem
5 Discuss the policy tools available to solve the problem
6 Predict the first and higher-order impacts of potential technology and policy solutions
12 Definitions
This technology assessment makes use of several terms and abbreviations In order to be
precise in the use of terms the following definitions are provided
bull Sustainability - Seeking to meet the needs of the present without compromising the
ability of future generations to meet their own needs
bull Pointsource - Pollution from a geographically localized discharge For example
a smokestack represents an atmospheric pointsource and a sewage treatment plant
represents an aquatic pointsource
bull Non-pointsource - Pollution from a geographically distributed discharge For ex-
ample land application of fertilizers is a non-pointsource discharge of nitrogen and
other nutrients
Managing Agricultural Water Impacts 3
bull Effluent - Any pollution-containing discharge of water from an engineered process
such as irrigation industrial production or municipal sewage treatment
bull Aquifer - A porous subterranean region saturated with groundwater
bull Surface water - Water available in streams rivers lakes and reservoirs
bull Best management practices (BMPs) - Ways in which agricultural production
methods can be altered to minimize negative water impacts
13 Problem Statement
Agricultural operations including animal and crop farming are important contributors to
the depletion of water resource quality and quantity in the United States Agriculture
represents approximately 40 of total US water demand and irrigation is the largest
consumptive water use Agricultural operations have been identified by the Environmental
Protection Agency as the leading source of water quality impairment to rivers and lakes
While reliable quantification of specific water quality and quantity impacts is gener-
ally unavailable the water resource research community agrees that the following crucial
problems are directly relevant to agriculture
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater overpumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
4 Managing Agricultural Water Impacts
bull Present United States water policies are insufficient to ensure future water supply
security
This technology assessment explores the options available to the federal government to
effect a move toward sustainable agricultural water management in light of the problems
listed above
14 Stakeholders
Because water is necessary for life all living things are stakeholders in this technology
assessment in the broadest possible sense For the purposes of this report stakeholders
are classified into groups that can be expected to share similar goals regarding agricultural
water resource policies The rights-holders most directly affected by the issues examined in
this report are
bull Agricultural producers and related industries - Farmers and the industries who
supply farm-related products are primary stakeholders Producers directly influence
water resources through agricultural withdrawal use and discharge
bull Municipal water users - The second-largest water demand after agriculture is mu-
nicipalities Clean drinking water is distributed to residences as well as industrial
operations Municipalities often compete directly with agriculture in water-scarce
regions
bull Federal state and local government - Water resources are managed by a variety
of governmental agencies Because water is a resource crucial to national security the
government is a central stakeholder Laws respecting water are passed at all levels of
government with corresponding jurisdictions of enforcement
bull Indigenous groups - Treaty agreements allocate water rights to indigenous groups
across the country In some regions these stakeholders have been under pressure from
agriculture and municipalities to relinquish their claims
Managing Agricultural Water Impacts 5
bull Environmental advocacy groups - Water quality and quantity issues related to
agriculture have wide-ranging impacts on the environment Individuals seeking to
protect the environment constitute a stakeholder group that regularly participates in
the formulation of US policy
bull US trade partners - As an importer and exporter of products on the world market
changes in the cost or quantity of production of agricultural goods in the United States
will affect other nations
15 Problem Categories
The problems associated with agricultural water use are arranged in this technology as-
sessment in terms of the water cycle of the United States This water cycle begins with
a source proceeds to a use and terminates with a discharge After providing background
and context for the broad range of agricultural water problems the report details some es-
pecially important first-order and higher-order impacts which result from current national
policies and practices The selected impacts focus on the withdrawal of groundwater and
the diversion of surface water for agricultural use
16 Technology Tools
Chapter 4 offers a study of the technologies available for increasing the quantity of water
available increasing the efficiency of use and limiting the impacts of agricultural pollution
The state of the art in agricultural technology is presented in order to provide background
for technology-based policy recommendations Ultimately most of the policies offered by
this technology assessment are not technology-focused since broader structural changes in
agricultural production are found to be needed to bring about water resource sustainability
6 Managing Agricultural Water Impacts
17 Priority Policy Options
This technology assessment concludes with an examination of eleven priority policy options
available to the Congress to help bring about sustainable water management in the United
States The policy options are called ldquopriorityrdquo because they are identified as those most
likely to be highly effective or cost-efficient in acheiving national water resource sustainabil-
ity These policies were developed through a synthesis of the information presented in the
following chapters along with an understanding of the type of policy tools available to the
Congress The priority policy option are analyzed in terms of their anticipated first-order
and higher-order policy impacts
Chapter 2
Problem Background
To establish agricultural water management as a priority subject for national policy atten-
tion this report first examines the historical context present situation and quantitative
significance of selected water resource problems in the United States This chapter is orga-
nized by following the mass flow of water from source to use to discharge
bull SourcesmdashSurface water and groundwater the two most significant water sources
for agriculture are described along with national usage trends and implications for
specific regions of the country
bull UsesmdashIrrigation the primary use of water withdrawn for agricultural production is
quantified and the potential for increases in efficiency is discussed
bull DischargesmdashThe fate of agricultural water supplies is examined with regard to quan-
tity loss and pollution contributions
Before an analysis of these areas it is important to understand the degree to which a
national water balance can be quantified By understanding the difficulties involved with
modeling the water cycle and using this data to project future water trends policy makers
will be better prepared to appreciate and to act on the information contained in this report
7
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
2 Managing Agricultural Water Impacts
that the country will soon face a crisis in both water quality and water quantity unless
current policies and practices are amended
This problem-based technology assessment seeks to analyze the impacts of agricultural
water use in the United States and to propose solutions to effectively manage agricultural
water resources The goals of this assessment are as follows
1 Establish the problem as quantitatively as possible
2 Provide background and context for the problem aspects
3 Describe the direct and higher-order impacts of the problem
4 Examine the technologies available to solve the problem
5 Discuss the policy tools available to solve the problem
6 Predict the first and higher-order impacts of potential technology and policy solutions
12 Definitions
This technology assessment makes use of several terms and abbreviations In order to be
precise in the use of terms the following definitions are provided
bull Sustainability - Seeking to meet the needs of the present without compromising the
ability of future generations to meet their own needs
bull Pointsource - Pollution from a geographically localized discharge For example
a smokestack represents an atmospheric pointsource and a sewage treatment plant
represents an aquatic pointsource
bull Non-pointsource - Pollution from a geographically distributed discharge For ex-
ample land application of fertilizers is a non-pointsource discharge of nitrogen and
other nutrients
Managing Agricultural Water Impacts 3
bull Effluent - Any pollution-containing discharge of water from an engineered process
such as irrigation industrial production or municipal sewage treatment
bull Aquifer - A porous subterranean region saturated with groundwater
bull Surface water - Water available in streams rivers lakes and reservoirs
bull Best management practices (BMPs) - Ways in which agricultural production
methods can be altered to minimize negative water impacts
13 Problem Statement
Agricultural operations including animal and crop farming are important contributors to
the depletion of water resource quality and quantity in the United States Agriculture
represents approximately 40 of total US water demand and irrigation is the largest
consumptive water use Agricultural operations have been identified by the Environmental
Protection Agency as the leading source of water quality impairment to rivers and lakes
While reliable quantification of specific water quality and quantity impacts is gener-
ally unavailable the water resource research community agrees that the following crucial
problems are directly relevant to agriculture
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater overpumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
4 Managing Agricultural Water Impacts
bull Present United States water policies are insufficient to ensure future water supply
security
This technology assessment explores the options available to the federal government to
effect a move toward sustainable agricultural water management in light of the problems
listed above
14 Stakeholders
Because water is necessary for life all living things are stakeholders in this technology
assessment in the broadest possible sense For the purposes of this report stakeholders
are classified into groups that can be expected to share similar goals regarding agricultural
water resource policies The rights-holders most directly affected by the issues examined in
this report are
bull Agricultural producers and related industries - Farmers and the industries who
supply farm-related products are primary stakeholders Producers directly influence
water resources through agricultural withdrawal use and discharge
bull Municipal water users - The second-largest water demand after agriculture is mu-
nicipalities Clean drinking water is distributed to residences as well as industrial
operations Municipalities often compete directly with agriculture in water-scarce
regions
bull Federal state and local government - Water resources are managed by a variety
of governmental agencies Because water is a resource crucial to national security the
government is a central stakeholder Laws respecting water are passed at all levels of
government with corresponding jurisdictions of enforcement
bull Indigenous groups - Treaty agreements allocate water rights to indigenous groups
across the country In some regions these stakeholders have been under pressure from
agriculture and municipalities to relinquish their claims
Managing Agricultural Water Impacts 5
bull Environmental advocacy groups - Water quality and quantity issues related to
agriculture have wide-ranging impacts on the environment Individuals seeking to
protect the environment constitute a stakeholder group that regularly participates in
the formulation of US policy
bull US trade partners - As an importer and exporter of products on the world market
changes in the cost or quantity of production of agricultural goods in the United States
will affect other nations
15 Problem Categories
The problems associated with agricultural water use are arranged in this technology as-
sessment in terms of the water cycle of the United States This water cycle begins with
a source proceeds to a use and terminates with a discharge After providing background
and context for the broad range of agricultural water problems the report details some es-
pecially important first-order and higher-order impacts which result from current national
policies and practices The selected impacts focus on the withdrawal of groundwater and
the diversion of surface water for agricultural use
16 Technology Tools
Chapter 4 offers a study of the technologies available for increasing the quantity of water
available increasing the efficiency of use and limiting the impacts of agricultural pollution
The state of the art in agricultural technology is presented in order to provide background
for technology-based policy recommendations Ultimately most of the policies offered by
this technology assessment are not technology-focused since broader structural changes in
agricultural production are found to be needed to bring about water resource sustainability
6 Managing Agricultural Water Impacts
17 Priority Policy Options
This technology assessment concludes with an examination of eleven priority policy options
available to the Congress to help bring about sustainable water management in the United
States The policy options are called ldquopriorityrdquo because they are identified as those most
likely to be highly effective or cost-efficient in acheiving national water resource sustainabil-
ity These policies were developed through a synthesis of the information presented in the
following chapters along with an understanding of the type of policy tools available to the
Congress The priority policy option are analyzed in terms of their anticipated first-order
and higher-order policy impacts
Chapter 2
Problem Background
To establish agricultural water management as a priority subject for national policy atten-
tion this report first examines the historical context present situation and quantitative
significance of selected water resource problems in the United States This chapter is orga-
nized by following the mass flow of water from source to use to discharge
bull SourcesmdashSurface water and groundwater the two most significant water sources
for agriculture are described along with national usage trends and implications for
specific regions of the country
bull UsesmdashIrrigation the primary use of water withdrawn for agricultural production is
quantified and the potential for increases in efficiency is discussed
bull DischargesmdashThe fate of agricultural water supplies is examined with regard to quan-
tity loss and pollution contributions
Before an analysis of these areas it is important to understand the degree to which a
national water balance can be quantified By understanding the difficulties involved with
modeling the water cycle and using this data to project future water trends policy makers
will be better prepared to appreciate and to act on the information contained in this report
7
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 3
bull Effluent - Any pollution-containing discharge of water from an engineered process
such as irrigation industrial production or municipal sewage treatment
bull Aquifer - A porous subterranean region saturated with groundwater
bull Surface water - Water available in streams rivers lakes and reservoirs
bull Best management practices (BMPs) - Ways in which agricultural production
methods can be altered to minimize negative water impacts
13 Problem Statement
Agricultural operations including animal and crop farming are important contributors to
the depletion of water resource quality and quantity in the United States Agriculture
represents approximately 40 of total US water demand and irrigation is the largest
consumptive water use Agricultural operations have been identified by the Environmental
Protection Agency as the leading source of water quality impairment to rivers and lakes
While reliable quantification of specific water quality and quantity impacts is gener-
ally unavailable the water resource research community agrees that the following crucial
problems are directly relevant to agriculture
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater overpumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
4 Managing Agricultural Water Impacts
bull Present United States water policies are insufficient to ensure future water supply
security
This technology assessment explores the options available to the federal government to
effect a move toward sustainable agricultural water management in light of the problems
listed above
14 Stakeholders
Because water is necessary for life all living things are stakeholders in this technology
assessment in the broadest possible sense For the purposes of this report stakeholders
are classified into groups that can be expected to share similar goals regarding agricultural
water resource policies The rights-holders most directly affected by the issues examined in
this report are
bull Agricultural producers and related industries - Farmers and the industries who
supply farm-related products are primary stakeholders Producers directly influence
water resources through agricultural withdrawal use and discharge
bull Municipal water users - The second-largest water demand after agriculture is mu-
nicipalities Clean drinking water is distributed to residences as well as industrial
operations Municipalities often compete directly with agriculture in water-scarce
regions
bull Federal state and local government - Water resources are managed by a variety
of governmental agencies Because water is a resource crucial to national security the
government is a central stakeholder Laws respecting water are passed at all levels of
government with corresponding jurisdictions of enforcement
bull Indigenous groups - Treaty agreements allocate water rights to indigenous groups
across the country In some regions these stakeholders have been under pressure from
agriculture and municipalities to relinquish their claims
Managing Agricultural Water Impacts 5
bull Environmental advocacy groups - Water quality and quantity issues related to
agriculture have wide-ranging impacts on the environment Individuals seeking to
protect the environment constitute a stakeholder group that regularly participates in
the formulation of US policy
bull US trade partners - As an importer and exporter of products on the world market
changes in the cost or quantity of production of agricultural goods in the United States
will affect other nations
15 Problem Categories
The problems associated with agricultural water use are arranged in this technology as-
sessment in terms of the water cycle of the United States This water cycle begins with
a source proceeds to a use and terminates with a discharge After providing background
and context for the broad range of agricultural water problems the report details some es-
pecially important first-order and higher-order impacts which result from current national
policies and practices The selected impacts focus on the withdrawal of groundwater and
the diversion of surface water for agricultural use
16 Technology Tools
Chapter 4 offers a study of the technologies available for increasing the quantity of water
available increasing the efficiency of use and limiting the impacts of agricultural pollution
The state of the art in agricultural technology is presented in order to provide background
for technology-based policy recommendations Ultimately most of the policies offered by
this technology assessment are not technology-focused since broader structural changes in
agricultural production are found to be needed to bring about water resource sustainability
6 Managing Agricultural Water Impacts
17 Priority Policy Options
This technology assessment concludes with an examination of eleven priority policy options
available to the Congress to help bring about sustainable water management in the United
States The policy options are called ldquopriorityrdquo because they are identified as those most
likely to be highly effective or cost-efficient in acheiving national water resource sustainabil-
ity These policies were developed through a synthesis of the information presented in the
following chapters along with an understanding of the type of policy tools available to the
Congress The priority policy option are analyzed in terms of their anticipated first-order
and higher-order policy impacts
Chapter 2
Problem Background
To establish agricultural water management as a priority subject for national policy atten-
tion this report first examines the historical context present situation and quantitative
significance of selected water resource problems in the United States This chapter is orga-
nized by following the mass flow of water from source to use to discharge
bull SourcesmdashSurface water and groundwater the two most significant water sources
for agriculture are described along with national usage trends and implications for
specific regions of the country
bull UsesmdashIrrigation the primary use of water withdrawn for agricultural production is
quantified and the potential for increases in efficiency is discussed
bull DischargesmdashThe fate of agricultural water supplies is examined with regard to quan-
tity loss and pollution contributions
Before an analysis of these areas it is important to understand the degree to which a
national water balance can be quantified By understanding the difficulties involved with
modeling the water cycle and using this data to project future water trends policy makers
will be better prepared to appreciate and to act on the information contained in this report
7
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
4 Managing Agricultural Water Impacts
bull Present United States water policies are insufficient to ensure future water supply
security
This technology assessment explores the options available to the federal government to
effect a move toward sustainable agricultural water management in light of the problems
listed above
14 Stakeholders
Because water is necessary for life all living things are stakeholders in this technology
assessment in the broadest possible sense For the purposes of this report stakeholders
are classified into groups that can be expected to share similar goals regarding agricultural
water resource policies The rights-holders most directly affected by the issues examined in
this report are
bull Agricultural producers and related industries - Farmers and the industries who
supply farm-related products are primary stakeholders Producers directly influence
water resources through agricultural withdrawal use and discharge
bull Municipal water users - The second-largest water demand after agriculture is mu-
nicipalities Clean drinking water is distributed to residences as well as industrial
operations Municipalities often compete directly with agriculture in water-scarce
regions
bull Federal state and local government - Water resources are managed by a variety
of governmental agencies Because water is a resource crucial to national security the
government is a central stakeholder Laws respecting water are passed at all levels of
government with corresponding jurisdictions of enforcement
bull Indigenous groups - Treaty agreements allocate water rights to indigenous groups
across the country In some regions these stakeholders have been under pressure from
agriculture and municipalities to relinquish their claims
Managing Agricultural Water Impacts 5
bull Environmental advocacy groups - Water quality and quantity issues related to
agriculture have wide-ranging impacts on the environment Individuals seeking to
protect the environment constitute a stakeholder group that regularly participates in
the formulation of US policy
bull US trade partners - As an importer and exporter of products on the world market
changes in the cost or quantity of production of agricultural goods in the United States
will affect other nations
15 Problem Categories
The problems associated with agricultural water use are arranged in this technology as-
sessment in terms of the water cycle of the United States This water cycle begins with
a source proceeds to a use and terminates with a discharge After providing background
and context for the broad range of agricultural water problems the report details some es-
pecially important first-order and higher-order impacts which result from current national
policies and practices The selected impacts focus on the withdrawal of groundwater and
the diversion of surface water for agricultural use
16 Technology Tools
Chapter 4 offers a study of the technologies available for increasing the quantity of water
available increasing the efficiency of use and limiting the impacts of agricultural pollution
The state of the art in agricultural technology is presented in order to provide background
for technology-based policy recommendations Ultimately most of the policies offered by
this technology assessment are not technology-focused since broader structural changes in
agricultural production are found to be needed to bring about water resource sustainability
6 Managing Agricultural Water Impacts
17 Priority Policy Options
This technology assessment concludes with an examination of eleven priority policy options
available to the Congress to help bring about sustainable water management in the United
States The policy options are called ldquopriorityrdquo because they are identified as those most
likely to be highly effective or cost-efficient in acheiving national water resource sustainabil-
ity These policies were developed through a synthesis of the information presented in the
following chapters along with an understanding of the type of policy tools available to the
Congress The priority policy option are analyzed in terms of their anticipated first-order
and higher-order policy impacts
Chapter 2
Problem Background
To establish agricultural water management as a priority subject for national policy atten-
tion this report first examines the historical context present situation and quantitative
significance of selected water resource problems in the United States This chapter is orga-
nized by following the mass flow of water from source to use to discharge
bull SourcesmdashSurface water and groundwater the two most significant water sources
for agriculture are described along with national usage trends and implications for
specific regions of the country
bull UsesmdashIrrigation the primary use of water withdrawn for agricultural production is
quantified and the potential for increases in efficiency is discussed
bull DischargesmdashThe fate of agricultural water supplies is examined with regard to quan-
tity loss and pollution contributions
Before an analysis of these areas it is important to understand the degree to which a
national water balance can be quantified By understanding the difficulties involved with
modeling the water cycle and using this data to project future water trends policy makers
will be better prepared to appreciate and to act on the information contained in this report
7
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 5
bull Environmental advocacy groups - Water quality and quantity issues related to
agriculture have wide-ranging impacts on the environment Individuals seeking to
protect the environment constitute a stakeholder group that regularly participates in
the formulation of US policy
bull US trade partners - As an importer and exporter of products on the world market
changes in the cost or quantity of production of agricultural goods in the United States
will affect other nations
15 Problem Categories
The problems associated with agricultural water use are arranged in this technology as-
sessment in terms of the water cycle of the United States This water cycle begins with
a source proceeds to a use and terminates with a discharge After providing background
and context for the broad range of agricultural water problems the report details some es-
pecially important first-order and higher-order impacts which result from current national
policies and practices The selected impacts focus on the withdrawal of groundwater and
the diversion of surface water for agricultural use
16 Technology Tools
Chapter 4 offers a study of the technologies available for increasing the quantity of water
available increasing the efficiency of use and limiting the impacts of agricultural pollution
The state of the art in agricultural technology is presented in order to provide background
for technology-based policy recommendations Ultimately most of the policies offered by
this technology assessment are not technology-focused since broader structural changes in
agricultural production are found to be needed to bring about water resource sustainability
6 Managing Agricultural Water Impacts
17 Priority Policy Options
This technology assessment concludes with an examination of eleven priority policy options
available to the Congress to help bring about sustainable water management in the United
States The policy options are called ldquopriorityrdquo because they are identified as those most
likely to be highly effective or cost-efficient in acheiving national water resource sustainabil-
ity These policies were developed through a synthesis of the information presented in the
following chapters along with an understanding of the type of policy tools available to the
Congress The priority policy option are analyzed in terms of their anticipated first-order
and higher-order policy impacts
Chapter 2
Problem Background
To establish agricultural water management as a priority subject for national policy atten-
tion this report first examines the historical context present situation and quantitative
significance of selected water resource problems in the United States This chapter is orga-
nized by following the mass flow of water from source to use to discharge
bull SourcesmdashSurface water and groundwater the two most significant water sources
for agriculture are described along with national usage trends and implications for
specific regions of the country
bull UsesmdashIrrigation the primary use of water withdrawn for agricultural production is
quantified and the potential for increases in efficiency is discussed
bull DischargesmdashThe fate of agricultural water supplies is examined with regard to quan-
tity loss and pollution contributions
Before an analysis of these areas it is important to understand the degree to which a
national water balance can be quantified By understanding the difficulties involved with
modeling the water cycle and using this data to project future water trends policy makers
will be better prepared to appreciate and to act on the information contained in this report
7
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
6 Managing Agricultural Water Impacts
17 Priority Policy Options
This technology assessment concludes with an examination of eleven priority policy options
available to the Congress to help bring about sustainable water management in the United
States The policy options are called ldquopriorityrdquo because they are identified as those most
likely to be highly effective or cost-efficient in acheiving national water resource sustainabil-
ity These policies were developed through a synthesis of the information presented in the
following chapters along with an understanding of the type of policy tools available to the
Congress The priority policy option are analyzed in terms of their anticipated first-order
and higher-order policy impacts
Chapter 2
Problem Background
To establish agricultural water management as a priority subject for national policy atten-
tion this report first examines the historical context present situation and quantitative
significance of selected water resource problems in the United States This chapter is orga-
nized by following the mass flow of water from source to use to discharge
bull SourcesmdashSurface water and groundwater the two most significant water sources
for agriculture are described along with national usage trends and implications for
specific regions of the country
bull UsesmdashIrrigation the primary use of water withdrawn for agricultural production is
quantified and the potential for increases in efficiency is discussed
bull DischargesmdashThe fate of agricultural water supplies is examined with regard to quan-
tity loss and pollution contributions
Before an analysis of these areas it is important to understand the degree to which a
national water balance can be quantified By understanding the difficulties involved with
modeling the water cycle and using this data to project future water trends policy makers
will be better prepared to appreciate and to act on the information contained in this report
7
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Chapter 2
Problem Background
To establish agricultural water management as a priority subject for national policy atten-
tion this report first examines the historical context present situation and quantitative
significance of selected water resource problems in the United States This chapter is orga-
nized by following the mass flow of water from source to use to discharge
bull SourcesmdashSurface water and groundwater the two most significant water sources
for agriculture are described along with national usage trends and implications for
specific regions of the country
bull UsesmdashIrrigation the primary use of water withdrawn for agricultural production is
quantified and the potential for increases in efficiency is discussed
bull DischargesmdashThe fate of agricultural water supplies is examined with regard to quan-
tity loss and pollution contributions
Before an analysis of these areas it is important to understand the degree to which a
national water balance can be quantified By understanding the difficulties involved with
modeling the water cycle and using this data to project future water trends policy makers
will be better prepared to appreciate and to act on the information contained in this report
7
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
8 Managing Agricultural Water Impacts
Inputs Outputs
Precipitation Groundwater Pumping
Runoff Evaporation
Infiltration Transpiration
Seepage Streamflow
Table 21 The agricultural water cycle Inputs and outputs
21 The Challenge of Quantification
Identifying the nature of sustainable water resources in the United States is technically
challenging From an engineering standpoint a balance for watermdashjust like any other mass
quantitymdashcan be achieved by determining input output and accumulation within a defined
area While such a mass balance is conceptually simple the practice of determining input
output and accumulation quantities can be difficult and expensive The list of major water
inputs and outputs at least is straightforward and is shown in Table 21
The difficulty for researchers is to translate the available data into water input output
and accumulation rates for the various geographical regions of the United States These rates
are interdependent for example streamflow (output) is affected by the local aquifer level
(accumulation) which is in turn affected by infiltration rates (input) Obtaining a water
balance for even a single aquifer requires substantial data collection mathematical modeling
and uncertainty analysis to compensate for the necessary assumptions and simplifications
(Carter Tschakert and Morehouse 2000)
The interaction between groundwater and surface water is still an active area of geo-
physical research Where data is available competing models yield conflicting quantitative
analyses of US water resources In other cases data are not available to make detailed
analyses At present neither the United States Geological Survey nor the Environmental
Protection Agency have definitive position papers on the quantitative analysis of future
national water resource availability (USGS 2001a)
However there do exist some detailed local studies from which overall trends can be
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 9
gleaned In addition while researchers disagree about the quantity of water available and
the rate of water depletion nationally there are important points of general agreement
regarding US water resources (Frederick 1995)
bull Agricultural groundwater removal generally exceeds the natural recharge rate
bull Groundwater over-pumping causes irreversible land settling and loss of aquifer storage
capacity
bull Surface water diversion contributes to downstream ecosystem deterioration
bull Agricultural non-pointsource pollution is an important contributor to water quality
degradation
bull Artificially low water prices for agriculture promote water use inefficiency
bull Present United States water policies are insufficient to ensure future water supply
security
In support of the last point of agreement one author notes
The largest hindrances to effective water management in virtually all countries
are the outmoded economic and institutional policies (taxes subsidies and reg-
ulations) that shape public and private decisions development strategies and
resource use patterns (Stakhiv 1998)
This technology assessment discusses the above points of general agreement along with
the specific findings of regional studies as a foundation for justifying potential changes in
national policy The technological and policy tools available to address these issues are
explored and synthesized into a number of policy options The remainder of this chapter
will examine the foundational background and data on national water resource problems
thereby setting the stage for the analysis necessary to formulate effective policy
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
10 Managing Agricultural Water Impacts
Figure 21 Estimated use of water in the United States 1950ndash1990 (USGS published at
5-year intervals)
22 Agricultural Water Sources
221 Surface Water
Surface water is that portion of water available in ponds lakes rivers streams and reser-
voirs Nationally surface water provides 63 of all water used by agriculture as well as 63
of all water used for public supply (USGS 2001a) Surface water is diverted for agricultural
and municipal use by pipelines and constructed channels such as canals For example the
Central Arizona Project canal transports Colorado River water 336 miles from Lake Havasu
to Phoenix then south to Tucson (Gelt Henderson Seasholes Tellman and Woodard 1998)
The system uses 14 pumping stations to lift water a total of 2400 vertical feet and was con-
structed at a cost of $4 billion dollars to the federal government (Streatfeild 1998)
Problem Downstream Effects
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into substantial economic losses
(Simon 1998) Surface flow diversion along the Columbia River has resulted in US Fish
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 11
Figure 22 Aquifer locations in the western United States
and Wildlife Service purchases of upstream water rights for downstream flow augmentation
(USFWS 2001) Often the amount of water promised through right-holder contracts exceeds
the safe flow available In recent drought years the Colorado River has diminished to little
more than a trickle before reaching the Pacific Ocean leading to negative environmental
impacts in the Colorado delta ecosystem (CRWUA 2001)
222 Groundwater
Groundwater aquifers underlie most of the land in the United States as well as all over
the world The water available in these subsurface storage regions is vast the High Plains
aquifer in the midwestern US is thought to contain almost a quadrillion gallons of watermdash
nearly the capacity of Lake Huron (Buddemeier et al 2000) Unlike rapidly moving surface
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
12 Managing Agricultural Water Impacts
water groundwater flows slowly through soil and rock fissures This slow movement means
that while water can remain stored in an aquifer for thousands of years once an aquifer is
depleted it can take thousands of years to recharge (Kranz Hay and Goeke 1993) Aquifers
that recharge slowly such as the High Plains aquifer are called ldquofossil aquifersrdquo since they
are essentially finite resources similar to fossil fuel deposits (OTA 1983) Aquifer locations
in the western United States can be seen in Figure 22
Since the mid-1950rsquos when federally subsidized electric cooperatives made electricity
available in the US Midwest for irrigation pumping nationwide groundwater use as a
percentage of total water use has increased from 19 percent to about 31 percent (Bertoldi
and Leake 1993) Agriculture derives more than a third of its supply from this source In
addition aquifers supply 51 percent of all drinking water for the total population and 99
percent of drinking water for the rural population (USGS 2000)
Geographically groundwater withdrawals are concentrated in the western states which
account for 96 percent of all groundwater withdrawals nationally (OTT 2001) Groundwater
has enabled vast acres of arid and semi-arid land to be transformed into productive fields
Groundwater-fed irrigated farms make up almost a third of the total value for US crop
production (OrsquoDonnell and Rademaekers 1997)
Problem Groundwater Overdraft
According to the United States Geological Survey significant ground-water depletions have
occurred in the High Plains aquifer of the Midwest many areas in the Southwest (AZ CA
NM NV and TX) the Sparta aquifer in the Southeast (AR LA and MS) and in the
Chicago-Milwaukee area Studies estimate that current groundwater overdrafts in Arizona
total 25 million acre-feet per year approximately 50 in excess of maximum sustainable
yield (Carter et al 2000) A Kansas Geological Survey study projects that significant
regions of that state will have exhausted their groundwater supplies by 2025 (Buddemeier
et al 2000) In some areas of Nebraska groundwater levels have fallen almost 30 feet below
normal (Kranz et al 1993) The saturated thickness of the High Plains Aquifer has declined
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 13
by over 50 percent in some areas A bill seeking to establish the High Plains Groundwater
Resource Conservation Act introduced into the 107th Congress listed aquifer level declines
of over 100 feet between 1950 and 1997 as justification for legislative action (Congress 2001)
23 Agricultural Water Use
This section of the chapter first examines the general divisions among types of water use
before focusing on the primary agricultural use of water irrigation
Water uses can be separated into two broad categories
bull Withdrawal Uses Withdrawn water is as the name implies physically removed
from its source Examples of withdrawal uses include groundwater pumping and
surface water diversion for irrigation or municipal use Use of withdrawn water can
be further described as either consumptive or non-consumptive Non-consumptive
uses such as for municipal drinking water eventually return most of the withdrawn
water to the original source For example river water used for municipal drinking
water is mostly returned to the river as treated sewage Irrigation on the other hand
is a consumptive usemdashwater extracted from a river or an aquifer is largely consumed
via evapotranspiration It is therefore crucial that consumptive uses be performed in
the most efficient manner possible so as to minimize water loss
bull Non-Withdrawal Uses When non-withdrawal uses are considered electric power
plants become the largest users of water in the United States This is because thermal
power plants use vast quantities of water for cooling and hydroelectric plants use water
to drive gravity turbines However such uses do not require water to be withdrawn
from its source so they are generally not considered true ldquousersrdquo of water (Murray
1995) Additionally the use of bodies of water to receive and dilute discharges of
treated industrial or municipal waste is considered non-withdrawal
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
14 Managing Agricultural Water Impacts
Figure 23 1990 irrigation withdrawals as the percent of total freshwater withdrawals
(USGS 1990)
231 Irrigation
Agricultural irrigation is the single largest consumptive use of water in the United States
Irrigation in the US accounts for 40 of total national water use The relative regional
importance of irrigation withdrawals is shown in Figure 23
Problem Irrigation Efficiency
The vast quantities of water consumed in irrigation mean that any gains in efficiency can
substantially decrease water usage Worldwide irrigation is an average of 37 efficient the
average in the United States 50 is not much better (Postel 1985 Pimental 1997 11)
Only about 5 of the irrigated lands in the US use the most efficient irrigation methods
available (USDA 1998) If farmers across the country could raise total use efficiency to 90
it would reduce the nation water demand by upwards of 15
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 15
Problem Irrigation Subsidies
Federally subsidized electric cooperatives established under the New Deal program helped
bring low-cost electricity to the Great Plains regions of the United States Much of the
electricity brokered by the cooperatives went to power groundwater pumps that helped
transform arid plains into productive farmland (Rhodes and Wheeler 1996) Many of the
artificially low rate contracts between agricultural producers and electric suppliers were
guaranteed for 50 or 100 years and have not yet expired
Groundwater irrigation expanded the agricultural production capacity of the United
States but higher crop yields came with an environmental cost Indiscriminate pumping
of groundwater to support agriculture has led to severely depleted aquifer levels Today
nearly 30 percent of all US groundwater withdrawals occur within the High Plains aquifer
which underlies parts of Colorado Kansas Oklahoma New Mexico and Texas (McGuire
Stanton and Fischer 1999) As previously mentioned a Kansas research study has identified
significant areas of its aquifer which due to depletion will be unusable in 25 years or less
(Buddemeier et al 2000) Nevertheless the federal government continues to support na-
tionwide irrigation infrastructure and energy requirements with annual irrigation subsidies
totaling $22 billion dollars (Edwards and DeHaven 2001)
Problem Water Inefficient Crops
Analysis of water demands by agriculture requires an examination of the national cultiva-
tion of ldquowater inefficientrdquo crops The amount of water a crop transpires is dependent on
climate soil conditions and location Some crops have much greater water requirements
than others By shifting toward the production of more water efficient crops agriculture
could potentially reduce current and future national water demands Table 22 summarizes
the water efficiency of several common crops
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
16 Managing Agricultural Water Impacts
CropFood Water Requirement (kilograms water per kilo-
gram food)
Current US
Acres Har-
vested
Potato 500ndash1500 1128716
Wheat 900ndash2000 3185163
Alfalfa 900ndash2000 5977985
Sorghum 1100ndash1800 565327
CornMaize 1000ndash1800 10778245
Soybeans 1100ndash2000 4191102
Rice 1900ndash5000 3238026
Chicken 3500ndash5700 na
Beef 15000ndash70000 na
Table 22 Water consumption by food type (Gleik 2000 USDA 1998)
24 Agricultural Water Discharge
After rainfall events or irrigation some water will evaporate or be absorbed by plants while
the rest will leave the fields either by surface runoff or by infiltration into aquifers This
runoff and infiltration is often contaminated with fertilizers and pesticides that are used
in agricultural production Contaminated water pollutes surface water bodies as well as
groundwater aquifers reducing the quality of water available for future uses (USGS 2001b)
Agricultural pollution falls into the general category of non-pointsource pollution As
opposed to spatially concentrated pointsource pollution such as that generated by paper
mills or sewage treatment facilities non-pointsource pollution is geographically disperse
Because the pollution discharge occurs over a large area non-pointsource pollution is gen-
erally more difficult to manage and treat than its pointsource counterpart In addition the
effects of this pollution may take many years to notice since the environmental residency
and transport time for some toxins can be on the order of decades (USGS 2001b)
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 17
The US Environmental Protection Agency has declared non-pointsource pollution to
be the leading cause of water pollution in the United States with agriculture as the leading
contributor of non-pointsource pollutants into rivers and lakes (EPA 2001b) Agriculture is
also one of the least regulated dischargers of effluents primarily due to the difficult nature
of quantifying non-pointsource pollution
The problem of agricultural pollution pertains both to ground and surface water Ac-
cording to the Environmental Protection Agencyrsquos Fact Sheet for 1994 ldquo agriculture is
the leading source of impairment in the nationrsquos rivers affecting 72 of the impaired river
miles States attribute 56 of problems in lakes to agriculturerdquo (EPA 1994 2) The
Office of Technology Assessment agrees as stated in its document Environmental Tools for
Policy Makers ldquo[A]griculture is thought to be the single largest source of remaining river
and lake water quality problemsrdquo (OTA 1995 19)
With regards to groundwater according to the 1994 EPA report the most frequently
cited pollutants are (EPA 1994 4)
bull Nitrates (49 states)
bull Volatile organic compounds (48 states)
bull Petroleum products (46 states)
bull Metals (45 states)
bull Pesticides (43 states)
Of these the first and the last pertain directly to agriculture This report analyzes
analyze these two pollutants separately with an emphasis on the sources effects and the
potential for pollution removal or prevention
241 Nitrates
Nitrates are an essential component of fertilizers both man-made and natural (ie ma-
nure) However if nitrates become dissolved in irrigation or rainwater they can leach into
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
18 Managing Agricultural Water Impacts
groundwater or run off into surface water causing serious water quality degradation The
three main sources of nitrate contributions to the environment are as follows with the first
two sources directly resulting from agricultural production (Schrama 1998)
bull Application of manure to grazing and silage fields in livestock production
bull Use of fertilizers in agriculture
bull Deposition of NOx and NHy from atmospheric sources
Problem Nitrate Toxicity
Once ingested into the human body nitrates can be converted into compounds called ni-
trosamines which are known carcinogens In addition nitrates can be chemically reduced
in the bodies of human infants to nitrites which reduces the oxygen-carrying capacity of
hemoglobin Nitrate concentrations in drinking water in the United States are limited to
10 parts per million primarily to prevent infant blood problems (Schrama 1998) While
municipal drinking water treatment plants chemically remove nitrate rural drinking water
wells near agricultural operations are likely to have elevated nitrate levels (OrsquoToole 1998
USGS 2001b)
Problem Eutrophication
Nitrates are necessary nutrients for algae and phytoplankton growth Discharge of nitrates
to surface water bodies greatly accelerates the natural process of eutrophication causing
algal blooms which ultimately lead to depleted oxygen levels and generally poor water
quality Eutrophication contributes to fish kills loss of riparian habitat death of beneficial
aquatic insects and taste and odor problems Eutrophication also increases the treatment
costs of surface water for municipal consumption (Pimental 1997) In Europe where nitrates
have historically been a significant problem nitrate overload has resulted in decreased
diversity of flora and fauna (Schrama 1998)
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 19
Problem Animal Waste Management
The increasing density of animal agricultural operations has been an important factor in
nitrate pollution incidence For example the EPA estimates that one adult dairy cow
produces more than 5000 gallons of manure each year containing 200 pounds of nitrogen as
well as 43 pounds of phosphorus and 138 pounds of potassiummdashall of which are contributors
to water quality deterioration (NPS 1999)
Problem Rural Contamination
The USGS recently found that in 4 of the 33 major aquifers studied nitrate concentrations
in more than 15 percent of the samples tested exceeded the USEPA drinking-water standard
(USGS 2001b) All four aquifers are relatively shallow in agricultural areas and composed
of sand and gravel that is vulnerable to contamination by land application of fertilizers In
nearly one-half of the major aquifers sampled water from at least one well out of 20 to 30
wells exceeded the drinking-water standard Many of the major aquifers exhibiting high
nitrate concentrations were used for rural domestic water supply
242 Pesticides
Farmers use a wide variety of chemicals to control unwanted weeds and pests on their prop-
erty Herbicides insecticides rodenticides and fungicides all fall under the broad heading
of pesticides According to the EPA the United States spends a total of $119 billion per
year on pesticides Seventy percent of this total is used in agriculturemdashequivalent to about
$4400 per farm for 19 million farms (Aspelin and Grube 1999) The United States accounts
for almost one-third of pesticide use in the world with 18 pesticide manufactures 2200
formulators 17000 distributors and 375000 commercial applicators supplying pesticides
nationally The annual US pesticide application rate is approximately 800 million pounds
(Aspelin and Grube 1999)
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
20 Managing Agricultural Water Impacts
Figure 24 US pesticide usage in 1997 (Aspelin and Grube 1999)
Problem Human Toxicity of Pesticides
The compounds used in pesticides are frequently toxic to humans Pesticides ingested
aspirated or absorbed through the skin can cause harmful allergic reactions Organophos-
phates and carbamates two common forms of insecticide inhibit the production of the
enzyme cholinesterase important for controlling the function of the nervous system Addi-
tionally the class of pesticides known as bipyridyls cause severe lung tissue damage along
with kidney and liver problems Total recovery after exposure to pesticides may not occur
(Hetzel 1996)
Problem Widespread Contamination
Low levels of pesticides have been found in surface water in every region of the United States
Forty-three states have reported detecting traces of at least one of 143 pesticides and 21
by-products in groundwater (USGS 1995) Contamination is seasonal depending on the
timing of pesticide applications and the level of runoff based on precipitation levels In many
streams the annual average concentrations of pesticides are within regulatory standards for
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 21
drinking water but may exceed water quality standards during peak usage times However
quantifying these contamination levels is difficult The difficulties in quantifying the threat
of pesticides to water resources is explained by the USGS
Our ability to assess the significance of pesticides in surface waters is limited by
several factors
bull First water-quality criteria have not been established for most pesticides
and pesticide transformation products and existing criteria may be revised
as more is learned about the toxicity of these compounds
bull Second criteria are based on tests with individual pesticides and do not
account for possible cumulative effects if several different pesticides are
present
bull Finally many pesticides and most transformation products have not been
widely monitored in surface waters
These factors and the lack of data on long-term trends show significant gaps
in our understanding of the extent and significance of pesticide contamination
on surface waters The results of this analysis indicate a need for long-term
monitoring studies in which a consistent study design is used and more of the
currently used pesticides and their transformation products are targeted (USGS
1995)
25 Summary
This chapter has introduced the most significant agricultural water resource problems cur-
rently facing the United States A variety of issues related to agricultural water source
use and discharge were presented along with supporting data to quantify the relative im-
portance of each Having established the context and background for each problem this
technology assessment next examines selected impacts resulting from these problems
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
22 Managing Agricultural Water Impacts
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Chapter 3
Selected Problem Impacts
Besides the problem-specific impacts mentioned in the preceding chapter there are a variety
of general impacts that relate to many of the identified problems Groundwater overdraft
and surface water diversion are two such impacts This chapter examines the first-order and
higher-level consequences of groundwater overdraft and surface diversion in detail providing
more evidence that agricultural water impacts deserve the careful attention of US policy
makers
31 Impacts of Groundwater Overdraft
Groundwater overdraft occurs when water removal exceeds water recharge The slow natural
recharge rate of most aquifers and high rate of pumping has led to groundwater overdrafts in
most irrigated areas of the US over the past century Impacts associated with groundwater
overdraft are the results of falling water levels as the water stored in an aquifer is depleted
311 Higher Pumping Costs
As groundwater levels drop irrigators are forced to drill deeper wells in order to access the
water they require Greater depth increases construction and maintenance costs of wells In
addition larger pumps which draw more electricity are needed to raise the water Several
23
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
24 Managing Agricultural Water Impacts
Figure 31 Subsidence due to groundwater overdraft California 1925-1992 (Bertoldi and
Leake 1993)
million acres in the High Plains Aquifer region have already been taken out of production as
pumping costs have surpassed the value of the food grown with the water (Frederick 1995)
312 Land Subsidence
Water in an aquifer is under tremendous pressure from the weight of soil and water above
it When an aquifer is over-pumped the water that was supporting the soil above it is
removed and the structural integrity of the aquifer is reduced Without water pressure to
support it the land surface begins to settle and compress in a process called subsidence
When an aquifer collapses the pore spaces that once held water are eliminated meaning
that the storage capacity of that aquifer is lost forever Subsidence can appear as a small
local collapse or as broad regional lowering of the landrsquos surface height (USGS 1995)
Figure 31 illustrates the dramatic affect land subsidence can have This photo taken
in California shows the position of the land surface in 1925 1955 and 1977 In 1977
the regionrsquos farmers stopped using groundwater and instead switched to surface water
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 25
However during a drought between 1987 and 1992 farmers again began using groundwater
and again the land surface began to drop (Bertoldi and Leake 1993)
Land subsidence causes substantial damage to structures such as buildings roads and
buried pipes Additionally subsidence can disrupt water conveyance structures leading to
poor drainage and possible flooding The National Research Council estimates the annual
costs due to increased flooding and structural damage from land subsidence to be in excess
of $125 million This total does not include the estimated loss of property value due to
subsidence or related increases in farm operating costs According to USGS a more realistic
estimate would be closer to $400 million a year (Bertoldi and Leake 1993)
313 Depletion of Surface Water
Groundwater interacts with surface water by supplying streamflow and maintaining wet-
lands in times of low precipitation On average about 40 percent of the river flow na-
tionwide depends on groundwater (Phillips 2001) Over-pumping of aquifers can lead to
lowered stream and lake levels and to dessication of wetlands These impacts will be further
explored in the surface water depletion section
314 Degraded Aquifer Water Quality
The water quality is generally lower in the deeper parts of aquifers resulting in higher
filtration costs for agricultural as well as rural uses The concentration of mineral salts
in depleted aquifers can render the groundwater useless for many water supply purposes
Federal drinking-water standards require that total dissolved solids not exceed 500 parts
per million Agriculture also has specific limits although these vary based on the salinity
tolerance of different crops In general a salinity level of greater than 1000 ppm renders
water useless for most irrigation applications (Leonard 1986)
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
26 Managing Agricultural Water Impacts
32 Impacts of Surface Water Diversion
Often the amount of water promised through rights-holder contracts exceeds the safe flow
available For example the maximum allowable diversion of flow in the Colorado River is set
at 75 million acre-feet per year which is split between seven states Because the Colorado
is primarily fed by Rocky Mountain snowpack flow in the river can fluctuate significantly
between wet periods and drought In recent drought years the river has diminished to
little more than a trickle before reaching its delta and emptying into the Pacific Ocean
(CRWUA 2001)
321 Habitat Loss
Surface water provides habitat for wetland and riverine ecosystems which often include
threatened or endangered species A minimum flow is necessary to prevent loss of habitat
which in the case of the Pacific Salmon harvest can translate into economic losses The
Interior Department estimates that annual economic losses due to low streamflow in the
Columbia River are in the tens of millions of dollars (Simon 1998) Surface flow diversions
in the Columbia basin have forced the US Fish and Wildlife Service to purchase nearly
$10 million dollars worth of water rights over 5 years for downstream flow augmentation
(USFWS 2001)
322 Decreased Aquifer Recharge
In areas of low groundwater tables precipitation-fed lakes and streams lose water into their
aquifers When surface water is diverted for alternate uses the quantity of water available
for natural aquifer recharge decreases With less water entering the aquifer the water table
in the aquifer is likely to fall leading to the problems associated with groundwater overdraft
(USGS 1995)
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 27
323 Municipal Supply Problems
Communities that are forced to resort to diverted water supplies like Phoenix and Tucson
often suffer ill effects when new water sources are introduced The physical and chemical
composition of new water sources can cause substantial municipal problems For example
when Tucson first introduced water from the Central Arizona Project canal consumers
reported pipe damage water heaters and evaporative cooler clogging skin rashes and
aquarium and pool damage (Gelt et al 1998)
324 Pollution Concentration
In times of depleted surface flow nutrient contributions from both pointsource and non-
pointsource polluters are increased relative to streamflow The decreased dilution of nutri-
ents results in a greater likelihood of algal blooms dissolved oxygen depletion and other
negative effects associated with eutrophication (IEE 2001) Higher nutrient concentrations
also contribute to increased treatment costs for downstream municipal drinking water sys-
tems
33 Second-Order Impacts
331 Increasing Water Price
The commodity of water is subject to the economic law of supply and demand As water
becomes more scarce its price will increase Already some farmers have found it to be
more profitable to sell their water rights than to farm their land (Vaux Jr 1990) Population
growth accelerates water scarcity by increasing demand as has been seen in Arizona one of
the most rapidly growing and water-critical states (Gelt et al 1998) The director of Water
Programs at the US Environment and Energy Study Institute summarized the problem of
scarcity and uncertainty thusly
Now we come to the $64000 question or should I say the $64 billion or $164
billion question No one really knows how much water will cost But if we
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
28 Managing Agricultural Water Impacts
continue our past practices it will undoubtedly run into the hundreds of billions
(Goldberg 1994)
332 Loss of Farm Production
In 1980 cash receipts from marketing livestock and their products and crops in the 17
Western States accounted for approximately $593 billion or about 43 percent of the income
derived from farming in the United States (OTA 1983) In particular the United States
is dependent on the West to provide certain crops including 85 of the national demand
for wheat barley and sorghum (OTA 1983) If farmers in western states continue to sell
their water rights and take cropland out of production the United States will be losing an
important segment of food supply The country will increasingly be reliant upon imported
foodstuffs to meet its demand
333 Changes to Animal Agriculture
Scarcity of water will inflate grain prices which will affect stakeholders that depend on
grain availability including animal agriculture producers The costs of many foods will rise
with meat production perhaps the most significantly affected Cattle production requires 7
kilograms of grain for 1 kilogram of live weight pork and poultry are slightly more efficient
at 4 to 1 and 2 to 1 respectively (Brown 2001) Alternative sources of protein such as
aquaculture or plant-based meat substitutes may become more commonplace
334 Failure of Local Economies
Water transfers due to rising costs and facilitated water rights trading almost always results
in a net reduction of water available to agriculture While economic water use efficiency is
increased on a sate-wide or nation-wide basis the burdens of water transfers typically fall
solely on small rural communities In La Paz County Arizona a community impacted by
a net loss of water rights to large municipal areas nearly all individuals agreed with the
statement ldquoThe losses to the community associated with the transfer of water are of such
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 29
a nature that they cannot be compensatedrdquo (Gollehon 1999) The unemployment rate of
the county jumped 14 as a direct result of water transfers
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
30 Managing Agricultural Water Impacts
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Chapter 4
Technologies
Having described and quantified in preceding chapters the water resource problems to which
agriculture contributes in the United States this report next examines the technology tools
available for alleviating these problems The technologies are organized in terms of the
problem areas agricultural water sources uses and discharges
41 Water Sources Increasing Quantity
411 Desalination
One way to create new water resources is to reclaim water located in brackish aquifers or the
ocean by way of desalination The technology is available but costly Table 41 summarizes
the costs of desalination for various sources Over 500 desalination plants mostly located in
California Florida Texas and Arizona produce approximately 12 percent of the worldwide
output of desalinated water (CCC 1993)
Since farmers currently pay only about $70 per acre-foot of water the high cost of desali-
nation makes it unlikely that agriculture could subsist by using this technology However
in California desalination has proven useful in providing water during short-term emergency
shortages
Beyond the issue of cost desalination has a number of other problems
31
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
32 Managing Agricultural Water Impacts
Desalination Source Capital Cost ($) Product Cost ($acft)
Seawater 20300000 1300
Brackish groundwater 7000000ndash10000000 440mdash500
Municipal wastewater (excludes cost
of pretreatment and distribution)
6400000 540
Table 41 The typical costs of desalination 1992 dollars (CCC 1993)
bull Facilities must be constructed near the coasts which tend to be sensitive environ-
mental areas Plant and animal habitats could be disrupted by the presence of a
desalination plant
bull Facilities must dispose of the salts that are removed from raw water this highly
concentrated brine requires specialized disposal
bull Desalination is a very energy intensive process For example before the Santa Barbara
reverse-osmosis plant shut down it used about 6600 kWh of electricity per acre-foot
of water produced In states already suffering from energy crises these high electricity
demands make desalination a less attractive alternative (CCC 1993)
412 Dams and Reservoirs
Currently the United States has more than 75000 dams and reservoirs with a total storage
capacity of about 860 million acre-feet While these bodies of water also provide recre-
ational and power-generation uses many are primarily intended as water storage devices
By accommodating seasonal variations in streamflow reservoirs allow water resource ad-
ministrators to plan for the average downstream flow rate Despite their general utility
there are a number of points to consider about dams and reservoirs
bull Many of the best areas to build high capacity reservoirs have already been used
(OTA 1983)
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 33
bull Sedimentation the deposition of eroded rock is dropping reservoir capacity by about
15 million acre-feet each year (OTA 1983)
bull Dams require maintainance to prevent safety hazards to downstream populations and
habitats
bull There is growing environmental resistance to dams focused on their negative effects
to animal habitats and migration patterns
bull Surface evaporation rates put practical limits on the size of reservoirs A study of
US river basins suggests that the Lower Colorado the Upper Colorado and the Rio
Grande have already reached this point (OTA 1983)
Although reservoirs and dams have helped solve national water needs in the past these
points help explain why they may not be the best solution for the future (Frederick 1995)
413 Water Reuse
Water reuse consists of a set of technologies designed to facilitate three distinct kinds of
water recycling
bull Direct potable reuse
bull Direct non-potable reuse
bull Indirect potable and non-potable reuse
These technologies all apply mainly to municipal users They are treated as potential
solutions to agricultural problems in situations where high agricultural water use reduces
the supply available for municipalities
Direct potable reuse
The option of direct potable reuse is the most technically demanding and societally con-
tentious In direct potable reuse the effluent of a wastewater treatment plant is routed
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
34 Managing Agricultural Water Impacts
directly to the intake of a drinking-water treatment plant Because of the seemingly closed-
loop cycle this process achieves it is often called ldquotoilet-to-taprdquo (WRA 2001) However a
number of issues prevent widespread adoption of this technology
bull Direct potable reuse is technically demanding because wastewater requires more ex-
tensive treatment prior to re-introduction in the drinking water plant Typically
wastewater is discharged to receiving bodies of water such as lakes and rivers di-
rectly cycling the wastewater back into drinking water requires physical and chem-
ical treatment surpassing that necessary for surface water discharge (Baumann and
Dworkin 1978)
bull Direct potable reuse is societally contentious because of the negative associations of
wastewater Although many communities already practice ldquoindirect potable reuserdquo
because their drinking water intake lies downstream of another municipalityrsquos wastew-
ater plant the idea of direct reuse is often more upsetting Citizen group reactions
in areas where direct potable reuse has been proposed tend to be strongly negative
(WRA 2001)
bull While some of the initial upset over direct reuse can be attributed to a general igno-
rance of the realities of water treatment direct potable reuse does suffer some serious
questions regarding health and hygiene The dilution of pollutants by receiving bodies
of water in traditional water treatment plays a significant role in cleaning the water
A system that loops back a large quantity of its water volume has the risk of concen-
trating pollutants over time While EPA-limited pollutants and pathogens are closely
monitored there are other potential problem chemicals whose effects are unknown
For example many medications are excreted from the body and are detectable in
wastewater Such chemicals are not on the list of monitored pollutants but would
certainly be present in recycled wastewater (NRC 1998)
In summary direct potable reuse is the most extreme case of water recycling and is
at present used only in water-critical situations While toilet-to-tap systems do work in
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 35
theory and some pilot plants are presently being monitored they are generally an option
of last resort
Direct Non-potable Reuse
This option requires a similar level of treatment as traditional wastewater prior to discharge
into receiving bodies of water The technology involved is simply a second set of water pipes
that carry treated wastewater back to large-volume irrigators Golf courses office parks
and city gardens that typically use clean drinking water for irrigation can switch to treated
wastewater without measurable ill effects (Baumann and Dworkin 1978)
While it is possible for all domestic irrigators to switch to recycled wastewater for their
home irrigation the cost of running new non-potable water lines to individual residences
is thought to be prohibitive Cities with non-potable reuse typically sell wastewater to a
small number of large-volume users such as those previously mentioned The benefits of
non-potable reuse include minimizing the cost of drinking water treatment by decreasing the
demand and increasing the beauty of the community with a new source of irrigation water
Additionally some recycled water infiltrates into the groundwater helping to prevent the
damage associated with falling groundwater tables (WRA 2001)
One negative aspect of direct non-potable reuse is the accumulation of byproducts over
time in the irrigated soil If the recycled wastewater has a non-zero concentration of salts or
other chemicals those chemicals may accumulate over time where the water is applied Usu-
ally physical and biological processes in the soil offset this concern unless the concentration
of a pollutant is unusually high(Baumann and Dworkin 1978)
Another negative effect is the potential consumer confusion between potable and non-
potable water piping Mixing up potable and non-potable water pipes is a concern when
users of recycled water include ordinary residences Industrial users typically do not suffer
such problems but small children may drink from a home faucet that is intended solely
for irrigation water Because treated wastewater is not devoid of pathogens and harmful
chemicals the consequences of ingestion can be severe (NRC 1998)
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
36 Managing Agricultural Water Impacts
Indirect Potable and Non-potable Reuse ldquoAquifer Rechargerdquo
These two options are grouped together because the technology for achieving them is the
same Also known as ldquoaquifer rechargerdquo the two main technologies involved are reservoir
infiltration and groundwater injection Both methods of aquifer recharge aim to replace
groundwater supplies with treated wastewater In a region that experiences groundwater
depletion through pumping for irrigation or municipal use this option is especially desirable
Prior to recharge wastewater is treated to a higher degree than is required for surface
water discharge but not to finished drinking water standards The water is then piped to
large basins where it is allowed to infiltrate into the ground In regions with aquifers that
have barriers to surface recharge or where space for reservoirs is too expensive the water
is pumped down into the aquifer through injection wells While they are more energetically
expensive injection wells take up less space and can sometimes recharge greater quantities
of water than surface basins (WRA 2001)
Aquifer recharge protects against saltwater intrusion in coastal regions and helps to
prevent subsidence wherever it is employed There is typically a residence time of 5 years or
more between injection and re-withdrawal for potable or non-potable use during which time
natural physical and biological processes help clean the water of pathogens and chemicals
(NRC 1998)
42 Water Uses Improving Efficiency
The second part of the agricultural water cycle as outlined in Chapter Two is the use
phase If the efficiency of use is increased the magnitude of agricultural water impacts can
be decreased Two technological areas where efficiency gains are possible are irrigation and
bioengineering of crops
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 37
Irrigation Method Advantages Disadvantages
Surge Simple low setup costs low
energy
Tendency to over-irrigate
non-uniform distribution
Sprinkle Easier to control High initial costs
Drip High water efficiency high fre-
quency precise
High initial costs requires ex-
pert management prone to
clogging
Table 42 Irrigation methods
421 Irrigation
The main problem with irrigation is its low efficiency Table 42 summarizes the characteris-
tics of the irrigation methods described in this section generally higher efficiency methods
cost more and require more expertise Experiments in the Texas High Plains aquifer re-
gion have shown that a move to low pressure sprinklers low-energy precision application
sprinklers and drip irrigation systems can help farmers raise efficiencies from 60 (the
average efficiency for furrow irrigation systems) to 90 or 95 Farmers in the studies also
saw crop yields increase 10-15 These benefits resulted from reduced evaporation runoff
and seepage (Postel 1999 187)
Surface
Surface irrigation is the oldest and most widely used method of irrigation Also called
gravity irrigation or field flooding surface irrigation relies on the natural slope of a field to
distribute water Water is released at the head of a sloping field and is allowed to flow to
the other end
The efficiency of a surface irrigation system is dependent on the type of soil and the
slope of the field The soil serves two roles the first is distribution to convey the water to
other parts of the field and the second is infiltration the delivery of the water to the plant
roots Variations in the soilrsquos infiltration capacity lead to non-uniform water distribution
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
38 Managing Agricultural Water Impacts
making it necessary to over-irrigate some parts of a field in order to give adequate coverage
to the whole field (Crow 2000)
Surface irrigation systems have low energy requirements since most of the work is done
by gravity The energy required for surface irrigation is the energy needed to pump the
water to the distribution unit Initial setup costs for surface irrigation are generally low
Through terracing surface irrigation can be applied to sloping land as well though the
construction and maintenance of terraces requires added labor expense (Hillel 1987)
Furrow
In furrow irrigation the surface of the soil is shaped into rows of ldquofurrowsrdquo U or V-
shaped banks in the soil Furrows are separated with ridges upon which crops are planted
Depending on the size of ridges only about half of the surface is covered with water resulting
in less loss due to evaporation Furrows are generally sloped to promote gravity-driven water
distribution
The application and distribution of water for furrow systems is very similar to surface
irrigation Water partially flows downward under the furrows themselves and sideways
into the ridges However because there is no water flowing over the ridges themselves
evaporation of the water leads to saline deposits on the ridges Salination can hinder seed
germination and reduce crop growth For this reason furrow irrigation is often rotated with
other forms to facilitate leaching and removal of salt accumulations (Hillel 1987)
Surge
Surge irrigation is a modification to surface and furrow irrigation systems Instead of
flooding a field continuously the water is released in surges as the name implies This
method requires the addition of microprocessor-controlled surge valves The first pulse of
water creates a layer of mud that ldquosealsrdquo the soil allowing subsequent pulses to continue
down the field more quickly and uniformly Adding surge valves to existing systems has the
potential to increase efficiency by about 20 (Postel 1999 187)
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 39
Sprinkle
Sprinkle irrigation uses a spray or jet created by expelling water from a nozzle The spray is
broken up into droplets and acts like a simulated rainfall of controlled frequency intensity
duration and droplet size In sprinkle irrigation soil application is not the method of
conveyingdistributing water to the field Sprinkle systems are designed to apply water at
rates that do not exceed the soilrsquos rate of infiltration in order to prevent surface runoff
Sprinkle systems are often a practical alternative for sloped or shallow soils The unifor-
mity of application generally depends much more on sprinkler position and placement than
the soil type These systems are affected by wind and depending on the size of droplets
and the spray trajectory uniform distribution may be limited Additionally when water
applied by the sprinkler evaporates on a crop leaf it may deposit salts that cause leaf scorch
(Hillel 1987)
Sprinkle systems have high initial costs and maintenance requirements They also use
high operating pressures which is a large energy requirement However their ability to
work on most types of soil makes them desirable in a number of situations
Drip
Drip irrigation is a slower and more localized application of water Drip heads are carefully
placed precisely where plants need water Water is always released below the infiltration
rate of the soil so the drip method is very efficient losing little water to evaporation Water
is also released more frequently than in other irrigation methods (Crow 2000)
Drip irrigation offers a high degree of precision and control of water application Little
energy is required because the transmission system uses low water pressures However drip
irrigation systems are highly susceptible to clogging by suspended particles and biological
agents Water in drip irrigation systems must be filtered and there is a relatively high
maintenance cost in addition to high setup costs (Hillel 1987)
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
40 Managing Agricultural Water Impacts
422 Water-Thrifty Crops
Water lost through inefficiencies in irrigation is one area in which improvements are possible
Another option is to decrease the baseline amount of water that crops require for growth
as explored in Chapter 2 Some biotechnology companies are looking to do just that by
modifying stomata in the plant leaves in the hopes of reducing transpiration (water loss
through evaporation) (Postel 1999) Further research in this area could be fruitful
43 Water Discharge Reducing Pollution
The final phase of the agricultural water use cycle is discharge in which water returns by
runoff or seepage to the larger hydrologic cycle As described in Chapter Two this phase
is a problem inasmuch as the discharges carry pollutants like nitrates and pesticides
Since agriculture is a non-pointsource polluter its output generally cannot be collected
and treated Therefore those solutions typically applied to industrial and municipal pol-
luters are not useful in an agricultural setting Some agricultural pollution problems can
be mitigated by the adoption of best management practices (BMPs) which are the pri-
mary options available to alleviate non-pointsource pollution However most BMPs are
not technology-based in the traditional sense of ldquotechnologyrdquo BMPs include tilling fields
less frequently or planting alternating rows of corn and beans or placing ditches where sed-
iment will collect rather than run off into streams (Gale Line Osmond Coffey Spooner
Arnold Hoban and Wimberley 1993)
The more traditional technological options available to the farmer focus on requiring less
pesticides Crops can be genetically engineered to require fewer pesticides and new pesti-
cides can be developed that are more environmentally friendly A spokesman for Novartis
a biochemicals company asserts that ldquo[b]y just isolating the active isomer we have been
able to reduce the application rate of an established Novartis active ingredient by 50 and
achieve the same fungicidal effectrdquo (Samo 1997) However some bioengineered products
may lead to increased pesticide applications for instance Monsantorsquos ldquoRoundup Readyrdquo
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 41
line of soybeans has been made resistant to the pesticide effectively raising the maximum
amount that can be applied to a field (Altieri and Rosset 1999)
Bioengineering options are generally areas for future research there is presently no clear
technological solution to the issues of polluted agricultural discharges
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
42 Managing Agricultural Water Impacts
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Chapter 5
Priority Policy Options
To summarize before proceeding with policy options this technology assessment began
with a description of the importance of agriculture to the future of water resources in the
United States After framing the problem specific agricultural water issues were discussed
in light of their documented impacts Further analysis of the general impacts associated
with agricultural water demand illustrated the critical need for national policy attention
Potential technology tools available to help manage water resource availability use and
discharge were discussed along with their anticipated impacts
51 Policy Tools
This chapter first outlines the policy tools available to Congress in order to provide context
for the exploration of policy options Brief descriptions of regulatory subsidy-based and
informational policy tools are presented After introducing the tools a variety of specific
policy options that utilize those tools are explored along with their potential impacts
43
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
44 Managing Agricultural Water Impacts
511 Regulatory Tools
Permitting
Congress has traditionally delegated the power of permit issuance to a number of regulatory
agencies including the Department of Agriculture and Environmental Protection Agency
The mandate for those agencies rests however on the strength of the legislation they are
charged with executing such as the 1972 Clean Water Act or 1987 Water Quality Act
Congress can help manage agricultural water impacts by implementing new environmental
legislation calling for any one of a variety of nationwide agricultural permitting systems
Specific options for such legislation will be explored later in this chapter
Enforcement
In certain cases the existing laws aimed at limiting agricultural water impacts are so poorly
enforced as to be ineffective Regulations passed by the Congress must be accompanied by
the resources to provide effective enforcement In addition Congressionally-mandated peri-
odic reviews of nationwide permit enforcement processes can increase efficiency by revealing
weaknesses and redundancies in the enforcement system
Market Creation
Creating legal frameworks designed to let free-market forces effect positive changes is an
increasingly popular legislative option Such markets are possible in the areas of agricultural
water use and non-pointsource discharge For example water markets are institutional
frameworks for the exchange of water use rights If society refuses to incur the costs of
significant new water storage and conveyance facilities water markets are one way to manage
water demands within the existing supply system Even if new storage and conveyance
infrastructure is created water markets can help allocate water in an economically efficient
manner Additionally effluent trading markets for non-pointsource dischargers can reduce
water quality impacts and may help bring about better basin-level watershed management
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 45
512 Subsidy Tools
Research Funding
The federal government provides substantial funding for research grants to a number of
agencies including the National Science Foundation the Department of Agriculture and
the Environmental Protection Agency The use of such funding is largely discretionary
depending on the focus of the particular agency A Congressional push to increase research
efforts that pertain directly to managing agricultural water impacts could be effective in
focusing agency funding toward the areas outlined in this technology assessment
Producer Payments
Agricultural producers receive almost 75 billion dollars annually in farm subsidies from the
federal government A portion of this money is earmarked specifically for irrigation water
reducing the incentive for producers to adopt better water-management practices Some
subsidies go to the production of surplus crops which then must be bought back from the
producers as price supports A re-examination of the funding level and intended effects of
producer payments can help provide for national water use efficiency
Tax Breaks and Business Incentives
The government can also effect positive change in water management indirectly by providing
financial incentives to businesses By financially encouraging agricultural companies and
producers to independently undertake initiatives related to water management or waste
reduction increases in water use efficiency and pollution reduction can be expected Tax
breaks to companies that take financial risks in order to minimize negative water-related
impacts can be an effective use of federal money
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
46 Managing Agricultural Water Impacts
513 Informational Tools
Technical Advice and Oversight
The Congress can make informational resources available to aid in the creation and oper-
ation of successful water-management initiatives For example the water markets which
presently exist in the western states lack federal oversight This situation has prevented
some stakeholders from participating fully in the decision-making process that approves
water right transfers Federal officials can aid in the approval process by taking into ac-
count the larger societal effects of water transfers that are beyond the jurisdiction of state
officials Additionally technical resources can be made available to create a clearinghouse
of information for potential water-right or effluent-quota transfers helping to maximize
market efficiency
Educational Programs
A ten-year USDAUSEPA study into the effectiveness of BMPs to reduce non-pointsource
pollution discovered that education may be the most cost-effective way to decrease pollutant
levels A lack of information about the various BMPs available prevents some farmers from
voluntarily implementing these practices Significant quantifiable drops in non pointsource
pollution have been documented as a result of voluntary BMP compliance through educa-
tion The establishment of a nationwide producer education program is one example of a
potentially effective information-based policy available to the Congress
52 Policy Options
The following priority policy options emerged from a synthesis of the information contained
in preceding chapters Water resource policy formulation requires a thorough understanding
of the magnitude of agricultural water impacts and the potential for encouraging techno-
logical or non-technological solutions The options listed below explore the ways in which
Congress can use policy tools to implement these solutions thus providing for improved
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 47
water resource sustainability The policies are organized according to the type of water
resource problem they most directly address Each policy option is presented along with
its anticipated first-order and potential higher-order impacts
521 Quality-Focused Policies
Require permits for non-pointsource discharges
The US Supreme Court has consistently interpreted the Clean Water Act as establishing a
ldquocomprehensive and all-compassingrdquo framework for water pollution regulation irrespective
of whether a discharge is pointsource or non-pointsource EPA agrees that total maxi-
mum daily load (TMDL) permits are necessary to reduce the impact of non-pointsource
pollution Additionally EPA has performed a cost analysis which suggests that the costs
of implementing non-pointsource permitting and monitoring will largely be offset by the
economic advantages of limiting and managing TMDL pollution loads within watersheds
(Fox 2000) Besides limiting pollutant levels and leading to the positive effects associated
with reduced nutrient loads such a program would facilitate integrated basin-level manage-
ment a method of water quality planning that is recommended by numerous studies The
program will require implementation of BMPs along with the cost assistance and education
that is necessary to effect proper BMP introduction (Gale et al 1993) The establishment
of TMDLs is likely to be contentious as the requirements will fall more heavily on some
kinds of farms than others (EPA 1999)
Regulate pointsource animal agriculture under the Clean Water Act
Animal agriculture operations in the United States such as dairy feed lots and hog farms
are not allowed to discharge into surface water The resulting practice of land-application
of waste leads to leaching of nutrients which ultimately end up in ground and surface water
(Sutton and Joern 2001) By permitting animal operations under the regulations of the
Clean Water Act land application of concentrated waste will decrease ultimately reducing
nutrient contamination of ground and surface water The cost of treating wastewater for
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
48 Managing Agricultural Water Impacts
discharge under CWA regulations is higher than treating wastewater for land application
which will raise the price of some agricultural products (Williams 2001) The higher cost
of doing business will drive animal production out of the United States in cases where the
cost of shipping is less than the cost of compliance with regulations However the large
quantity of existing farm infrastructure may prevent farms from relocating in the short
term effectively canceling the risk of job and tax base losses (USDA 1997)
Legalize effluent trading among permit holders
Effluent markets present the possibility of reducing basin-wide pollutant discharge in a
flexible and market-driven manner By allowing the buying and selling of effluent dis-
charge capacity an effluent market system is inherently more efficient than other systems
founded on simple regulation Effluent markets that are already in place have applied all the
progressive-reduction tenets of regulation-based systems which demand reduced total emis-
sions (Inc 2001) Furthermore a market system will reduce the time and effort needed to
inspect factory equipment by measuring the total emissions from a given plant rather than
summing the outputs from specific pieces of equipment in that factory (RECLAIM 2001)
The effluent market will allow companies and industries that are unable to reduce their
emissions below requirements to remain in business albeit at an economic disadvantage
while still reducing the total area-wide emissions However because some emitters may
purchase permits for increased discharge pollution may increase in localized regions
522 Quantity-Focused Policies
Provide aid to develop a framework for water markets
While market-driven water transfers are presently legal and usually subject to the approval
of state authorities most states do not have an established process by which to consider
the impacts of water transfers to the broader society There is a need for informational and
monetary assistance to effect a more just process of rights trading since the present system
only addresses the concerns of ldquofirst-orderrdquo stakeholders such as the direct buyers and sellers
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 49
of water rights (Gollehon 1999) Economic studies of water markets indicate that overall
economic efficiency is improved on a state-wide level with a net loss of water available
for agricultural use However these studies note that economic costs and benefits fall on
different populations within the state Income loss is typically concentrated within sub-
county areas with some small farming communities severely impacted (Carter et al 2000)
Long lead times of notice prior to an actual water transfer seem to be one of the few methods
of mitigating the suffering of small farming communities In La Paz County Arizona where
water market transfers led to a 14 unemployment increase in a single year virtually all
residents responded affirmatively to the statement ldquoThe losses to the community associated
with the transfer of water are of such a nature that they cannot be compensatedrdquo (Charney
and Woodward 1990)
Fund the construction of municipal storage and reuse technologies
One way to offset the municipal supply-shortage caused by agricultural water use is to
aid municipalities with the construction of water storage and reuse infrastructure Aquifer
recharge programs underway in California have shown the ability to provide a long-term
renewable water supply (WRA 2001) Aquifer recharge and wastewater reuse are less viable
as alternatives in rural areas because of the high cost of infrastructure Funding of these
projects in water-critical regions similar to wastewater infrastructure funding provided by
Congress in the 1950s and 1960s will allow for the completion of projects that are too
expensive to depend solely on local funding (Baumann and Dworkin 1978) Use of taxpayer
money to assist a select area of the country may be objectionable to some but these
municipal storage and reuse projects will ease the demand on non-local sources minimizing
the diversion of surface water and the overdraft of groundwater (NRC 1998) However
this reduced demand may allow poor agricultural water use practices to continue since the
overall scarcity of water will be less dire
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
50 Managing Agricultural Water Impacts
Enforce existing groundwater pumping limits
The United States can be more strict in enforcing groundwater pumping limits established
in the Reclamation Reform Act (RRA) of 1982 Federal law outlined in the RRA only
allotted federally subsidized irrigation water to farms of 960 acres or less One report found
that Californiarsquos large farms have been consistently violating acreage limits by presenting
themselves as multiple small farms (Villarejo and Redmon 1989) The study found that
after the RRA was passed 49 of the land in Californiarsquos Westlands Water District were
still controlled by only 50 different operations resulting in an estimated average farm size of
1312 acres Successful enforcement of groundwater pumping limits would mean that only
farms that actually meet size requirements would receive water subsidizes Large farming
operations would not be allowed to bypass the RRA by ldquotechnicallyrdquo decreasing the size of
their farm on paper Large farms would have to pay full price for the water they withdraw
giving smaller-scale farms a competitive edge Smaller farm sizes have an added benefit of
improving social conditions in the rural west Researchers have shown that smaller farm
sizes are accompanied by better social conditions in the communities surrounding the farm
(Villarejo and Redmon 1989)
Alter current irrigation subsidies
Subsidies for irrigation in the past 100 years may be the most substantial contribution
to present groundwater scarcity issues Certainly federal irrigation subsidies are at least
the historical proximate if not ultimate cause of some important water problems in the
western United States (Hartmann and Goldstein 1994) Interior Department economists
have estimated that 38 of irrigation subsidies ($800 million) go toward the irrigation of
ldquosurplusrdquo cropsmdashcrops that the US Department of Agriculture pays other farmers not
to grow Payments for surplus crops average $15 billion annually (Edwards and DeHaven
2001) Thus the government unnecessarily spends at least $23 billion per year on irrigation-
related subsidies That total does not take into account the federal money required to assist
with alternate municipal water supplies or money to relieve municipal damage such as land
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 51
subsidence caused by aquifer over-pumping Reducing or eliminating irrigation subsidies
will result in a shift to the production of water-thrifty more highly-valued crops with
decreasing production of water-inefficient cereal crops Eliminating subsidies would also
drive many farmers out of business potentially leading to the failure of local economies
(Gollehon 1999)
Promote trade agreements which result in virtual water importation
When a product is imported or exported the water that was used to create the product
is carried along with it in a sense This concept is called ldquovirtual waterrdquo Water-poor
countries can reduce their agricultural water use by choosing to import crops that require
the most water to produce (Bouwer 2000) As water becomes more scarce in the United
States the crops production will gradually be forced to shift away from water-intensive
crops such as alfalfa The production of similar crops will shift to water-rich nations like
Canada (Allan 1997) By seeking to establish virtual-water importation now Congress
can ease the groundwater overdraft and surface diversion problems found mainly in the
Southwest The cost of importing grain will result in increased food prices and some
grain-producing farmers will be forced out of business (Bouwer 2000)
523 Comprehensive Policies
Implement farm-assist programs for BMP education and adoption
A 10-year study performed under the Rural Clean Water Program found that agricultural
producers most often fail to implement best management practices (BMPs) because they
lack information on the relative costs and benefits of BMPs (Gale et al 1993) When
agricultural extension agents worked with the producers to demonstrate the need for BMPs
most producers agreed to voluntarily implement the practices However it was found
to be crucial that federal or state money be available to defer the costs associated with
implementing technology-based BMPs (EPA 2001a) Producer education will result in
pollution-reduction goals being ldquointernalizedrdquo by producers which will lead to producers
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
52 Managing Agricultural Water Impacts
taking a more proactive role in pollution control The governmental assistance in defraying
implementation expenses will help prevent costs from being passed along to consumers and
will build positive relationships between producers and the agricultural extension agents
who seek to help them manage their operations (Council 2000)
Review the effectiveness of existing enforcement processes
At present some farms are inspected on a regular basis by the EPA and one or more
state-level bureaus Other farms may experience a lapse between inspections of as much
as several years (Brawdy 1998) This variation in inspection frequency leads some farm-
ers to discharge illegal amounts of pollution Often the discharges are unintentional but
in all cases the farms operate without suffering the consequences of breaching the stated
regulations It is presumed that a review of present enforcement effectiveness will show
that there are several potential ways in which the current permitting and review process
could be improved (FAO 2001) After making the changes identified in the review it will
be possible for government agencies on different levels (ie state-level and national level)
to pool their resources eliminate the duplication of work and effectively inspect all agri-
cultural producers (NPS 1999) This increased efficiency in inspection will help reduce the
number of discharge violations in a given area Fostering cooperation between producers
and multiple government agencies will also facilitate the development and distribution of
new techniques designed to reduce agricultural discharges Finally the government will
have increased potential for collecting revenue since fines can be collected in fairness once
all producers are being regularly inspected
Support agricultural water-related research
Research into agricultural technologies has yielded several recent developments for both
waste treatment and desalinationpurification (USBR 2001) Should research funding be
increased the pace of new developments is similarly expected to increase Results may
include decreased costs of waste treatment new methods for aquifer recharge or more
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 53
energy-efficient desalination technologies Research funding increases would give policy
makers new and better tools to address water quality and quantity issues in the United
States
Funding for water resource planning is also in need of augmentation This funding has
historically been misguided in two ways Typically money has been made available for only
one level of government to study the problem rather than allow for studies at different
scales (ie basin-wide state-wide and nation-wide) Additionally monies are usually set
aside to look at a specific water resource such as groundwater rather than to consider the
interrelated nature of the water resources in any given watershed (ASCE 2001) The funding
of more comprehensive studies such as this one is crucial if the nation is to successfully
manage future water demands
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
54 Managing Agricultural Water Impacts
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Bibliography
Allan J A 1997 lsquoVirtual waterrsquo A long term solution for water short Middle Eastern economies SOAS
Water Issues Study Group Occasional Papers httpwwwciaonetorgwpsaln02
Altieri M A and Rosset P 1999 Ten reasons why biotechnology will not ensure food security protect the
environment and reduce poverty in the developing world AgBioForum 2(3) httpwwwagbioforum
orgvol2no34altierihtm
ASCE 2001 Policy statements American Society of Civil Engineers httpwwwasceorgnews
policy-publiccfm
Aspelin A L and Grube A H 1999 Pesticide industry sales and usage 1996 and 1997 market estimates
United States Environmental Protection Agency
Baumann D D and Dworkin D M (eds) 1978 Planning for water reuse Maaroufa Press Chicago
Bertoldi and Leake 1993 Land subsidence from ground-water pumping United States Geological Service
waterwrusgsgovsubsidencels_3html
Bouwer H 2000 Integrated water management Emerging issues and challenges Journal of Agricultural
Water Management 45(1) 217ndash228
Brawdy B 1998 The Yakima a river wasted State doing little to ensure dairy animals arenrsquot polluting
river httpwwwtri-cityheraldcomyakimaday3story3html
Brown L R 2001 How water scarcity will shape the new century Water Science and Technology 43(4) 17ndash
22
Buddemeier R W et al 2000 An atlas of the Kansas High Plains aquifer Kansas Geological Survey
httpwwwkgsukanseduHighPlainsatlasindexhtml
Carter R H Tschakert P and Morehouse B J 2000 Assessing the sensitivity of the Southwestrsquos
urban water sector to climate variability Case studies in Arizona Institute for the Study of Planet
Earth University of Tucson Arizona CLIMAS Report Series CL1-00 httpwwwispearizonaedu
climasreportseriesindexhtml
55
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
56 Managing Agricultural Water Impacts
CCC 1993 Seawater desalination in California California Coastal Commission httpwwwcoastalca
govwebdesalrptdtitlehtmlTOCDesalination
Charney A H and Woodward G C 1990 Socioeconomic impacts of water farming on rural areas of
origin in Arizona American Journal of Agricultural Economics 72(5) 1193ndash99
Congress U 2001 High Plains Groundwater Resource Conservation Act 107th United States Congress S
1538 IS
Council C B 2000 Best funding practices for watershed management httpcerescagovbiodiv
TextOtherWwgpdf
Crow D 2000 Ancient irrigation httpwww-geologyucdavisedu~GEL115115CH17oldirrigation
html
CRWUA 2001 Arizona at a glance Colorado river profile Colorado River Water Users Association
httpcrwuamwddstcausazcrwua_azhtm
Edwards C and DeHaven T 2001 Farm subsidies at record levels as Congress considers new farm bill
Cato Institute Briefing Paper 70 wwwcatoorgpubsbriefsbp70pdf
EPA 1994 Fact sheet for 1994 United States Environmental Protection Agency
EPA 1999 Proposed regulatory revisions to the total maximum daily program United States Environmental
Protection Agency Office of Water Document 800-F-99-002 httpwwwepagovowowtmdltmdlfs
html
EPA 2001a A Guidebook of Financial Tools Section 6 Tools for Lowering Costs United States En-
vironmental Protection Agency Environmental Finance Program httpwwwepagovefinpage
guidbk98gbk6htm
EPA 2001b Non-point source program United States Environmental Protection Agency httpwwwepa
govregion4waternps
FAO 2001 Law and markets - improving the legal environment for marketing Improving regulatory frame-
works United Nations Food and Agriculture Organization httpwwwfaoorgwaicentfaoinfo
agricultagsAGSMlegalchap_6pdf
Fox J C 2000 Testimony of J Charles Fox Assistant Administrator for water US Environmental
Protection Agency httpwwwsenategov~epwfox_0518htm
Frederick K D 1995 Americarsquos water supply Status and prospects for the future Consequences 1(1)
Gale J Line D Osmond D Coffey S Spooner J Arnold J Hoban T and Wimberley R 1993
Evaluation of the experimental Rural Clean Water Program United States Environmental Protection
Agency httph2osparcwqncsueduinforcwpindexhtml EPA-841-R-93-005
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 57
Gelt J Henderson J Seasholes K Tellman B and Woodard G 1998 Water in the Tucson area
Seeking sustainability Water Resources Research Center College of Agriculture University of Arizona
httpagarizonaeduAZWATERpublicationssustainabilityreport_htmlcoverhtml
Gleik P H 2000 The Worldrsquos Water 2000-2001 Island Press Washington DC
Goldberg R 1994 Experts try to predict the future cost of water Proceedings of the Fifth National
Conference on Environmental Issues Water Our Next Crisis Academy of Natural Sciences www
acnatsciorgerdeafuture_COWhtml
Gollehon N R 1999 Water markets Implications for rural areas of the West Rural Development Per-
spectives 14(2)
Hartmann J R and Goldstein J H 1994 Western riparian wetlands The impact of federal programs on
wetlands httpwwwdoigovoepcwetlands2v2ch12html
Hetzel G 1996 Safe use of pesticides in agriculture Virginia Cooperative Extension Publication Number
442-036 httpwwwextvtedupubssafety442-036442-036html
Hillel D 1987 The Efficient Use of Water in Irrigation World Bank Washington DC
IEE 2001 Small watersheds network Nutrients Institute for Ecological Economics University of Maryland
httpieeumceseduAVEDUSWNModulesM2html
Inc L A 2001 The cleaner and greener program Emission trading 101 httpwwwcleanerandgreener
orgenvironmentemissiontradinghtm
Kranz W L Hay D R and Goeke J W 1993 Understanding groundwater Cooperative Extension
Institute of Agriculture and Natural Resources University of NebraskandashLincoln httpwwwianr
unledupubsWaterg1128htm
Leonard R 1986 Agriculture and groundwater quality Proceedings of the Focus Conference on Southeast-
ern Groundwater Issues pp 125ndash144
McGuire V L Stanton C P and Fischer B C 1999 Water-level changes in the High Plains aquifer 1980-
1996 United States Geological Survey httpnewaterusgsgovhighplainshp96_web_report
hp96_factsheethtm
Murray P (ed) 1995 Water Sources Principle and Practices of Water Supply Operations second edn
American Water Works Association Denver
NPS 1999 Idaho dairymenrsquos pledge to clean up their act pays off Nonpoint Source News-Notes Issue 57
NRC 1998 Issues in potable reuse The viability of augmenting drinking-water supplies with reclaimed
water National Research Council httpwwwnapedubooks0309064163htmlindexhtml
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
58 Managing Agricultural Water Impacts
OrsquoDonnell M and Rademaekers J 1997 Water use trends in the Southwestern United States 1950-
1990 United States Geological Survey httpgeochangeerusgsgovswimpactshydrology
water_use
OTA 1983 Water-related technologies for sustainable agriculture in US aridsemiarid lands United States
Congress Office of Technology Assessment
OTA 1995 Environmental policy tools United States Congress Office of Technology Assessment
OrsquoToole Jr L J 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht chapter 12 13
OTT 2001 Technologies affecting groundwater United States Office of Techology Transfer
Phillips N 2001 Groundwater amp surface water Understanding the interaction Conservation Technology
Information Center wwwcticpurdueeduKYWBrochuresGroundSurfacehtml
Pimental D e a 1997 Water resources Agriculture the environment and society BioScience 47(2) 97ndash
106
Postel S 1985 Conserving Water The Untapped Alternative Worldwatch Institute Washington DC
Postel S 1999 Pillar of Sand Can the Irrigation Miracle Last WW Norton and Company New York
RECLAIM 2001 Reclaim Regional clean air market (home page) httpwwwaqmdgovreclaim
reclaimhtml
Rhodes S L and Wheeler S E 1996 Rural electrification and irrigation in the US High Plains Journal
of Rural Studies 12(3) 311ndash317
Samo W 1997 Pesticides and agriculture httpwwwpmacnetsamohtm
Schrama G J (ed) 1998 Drinking Water Supply and Agricultural Pollution Kluwer Academic Publishers
Dordrecht
Simon B M 1998 Federal acquisition of water through voluntary transactions for environmental purposes
Contemporary Economic Policy pp 422ndash32
Stakhiv E Z 1998 Policy implications of climate change impacts on water resources management Water
Policy 1(2) 159ndash175
Streatfeild R 1998 Central Arizona Project pathfinder University of Arizona Law School httpwww
lawarizonaedulibraryLibraryInternetDocumentsPathfindersrstreatpathdeschtml
Sutton A L and Joern B C 2001 Land application of manure Purdue University Cooperative Extension
Service httphermesecnpurdueeducgiconvwqtestwq-16inascii
USBR 2001 Water technologies United States Bureau of Reclamation Water Treatment Engineering and
Research Group httpwwwusbrgovwatercontentc_techhtml
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-
Managing Agricultural Water Impacts 59
USDA 1997 NAFTArsquos impact on agriculture The first 3 years United States Department of Agriculture
Economic Research Service httpwwwersusdagovpublicationsagoutlooksep1997ao244e
USDA 1998 1998 farm amp ranch irrigation survey United States Department of Agriculture httpwww
nassusdagovcensuscensus97frisfrishtm
USFWS 2001 Fiscal year 2002 budget justifications United States Fish and Wildlife Service http
budgetfwsgovgreenbooktochtml
USGS 1990 National water-use maps United States Geological Survey httpwaterusgsgovwatuse
wumapscolorhtml
USGS 1995 Ground water studies United States Geological Survey httpwaterusgsgovwidhtml
GWhtmlHDR3
USGS 2000 A reconnaisance study of the effect of irrigated agriculture on water quality in the Ogallala
formation central High Plains aquifer United States Geological Service httpwebservercrusgs
govnawqahpgwfactsheetsMCMAHONFS1html
USGS 2001a Estimated use of water in the United States in 1995 United States Geological Service
httpwaterusgsgovwatusepdf1995html
USGS 2001b The quality of our nationrsquos waters Nutrients and pesticides United States Geological Survey
Circular 1225 httpwaterusgsgovpubscirccirc1225
Vaux Jr H 1990 The Changing Economics of Agricultural Water Use American Society of Agricultural
Engineers St Joseph Michigan pp 8ndash12
Villarejo D and Redmon J 1989 Missed opportunities squandered resources Why prosperity brought
water does not trickle-down in the California Central Valley httpwwwcirsincorg
Williams C M M 2001 Environmentally superior waste management technologies Animal and Poultry
Waste Management Center NCSU httpmarkascincsueduNCPorkConfwilliamshtm
WRA 2001 Home page The WateReuse Association httpwwwwatereuseorg
- Executive Summary
-
- Introduction
- Definitions
- Problem Statement
- Stakeholders
- Problem Categories
- Technology Tools
- Priority Policy Options
-
- Problem Background
-
- The Challenge of Quantification
- Agricultural Water Sources
-
- Surface Water
- Groundwater
-
- Agricultural Water Use
-
- Irrigation
-
- Agricultural Water Discharge
-
- Nitrates
- Pesticides
-
- Summary
-
- Selected Problem Impacts
-
- Impacts of Groundwater Overdraft
-
- Higher Pumping Costs
- Land Subsidence
- Depletion of Surface Water
- Degraded Aquifer Water Quality
-
- Impacts of Surface Water Diversion
-
- Habitat Loss
- Decreased Aquifer Recharge
- Municipal Supply Problems
- Pollution Concentration
-
- Second-Order Impacts
-
- Increasing Water Price
- Loss of Farm Production
- Changes to Animal Agriculture
- Failure of Local Economies
-
- Technologies
-
- Water Sources Increasing Quantity
-
- Desalination
- Dams and Reservoirs
- Water Reuse
-
- Water Uses Improving Efficiency
-
- Irrigation
- Water-Thrifty Crops
-
- Water Discharge Reducing Pollution
-
- Priority Policy Options
-
- Policy Tools
-
- Regulatory Tools
- Subsidy Tools
- Informational Tools
-
- Policy Options
-
- Quality-Focused Policies
- Quantity-Focused Policies
- Comprehensive Policies
-