The Importance of Watershed The Importance of Watershed Modeling for Conservation PolicyModeling for Conservation Policy

OrOr

What is an Economist Doing at a What is an Economist Doing at a SWAT Workshop?SWAT Workshop?

Watershed Models Critical for Watershed Models Critical for Conservation Policy AnalysisConservation Policy Analysis

Conservation policies need to be cost-effectiveConservation policies need to be cost-effective Targeting, Targeting, watershed trading,watershed trading, put practices on sites that achieve greatest gain for the costput practices on sites that achieve greatest gain for the cost

Policy AssessmentPolicy Assessment Section 305(b) of the Clean Water Act requires states to Section 305(b) of the Clean Water Act requires states to

prepare estimates prepare estimates “ “of the environmental, economic and social costs and benefits of the environmental, economic and social costs and benefits

needed to achieve the objectives of the CWA and an estimate of the needed to achieve the objectives of the CWA and an estimate of the date of such achievement.” date of such achievement.”

Iowa: Non-point Source Needs Iowa: Non-point Source Needs AssessmentAssessment

CARD is working with CARD is working with DNR to provide such DNR to provide such an estimate; how?an estimate; how?

Combining simple Combining simple economic models of economic models of costs with SWATcosts with SWAT

Steps: Non-point Source Needs Steps: Non-point Source Needs AssessmentAssessment

Establish baseline, calibrate SWAT Establish baseline, calibrate SWAT Scenarios:Scenarios:

1.1. Identify set of conservation practices in each Identify set of conservation practices in each watershed, compute cost of those practiceswatershed, compute cost of those practices

2.2. Predict flow and water quality (sediment and Predict flow and water quality (sediment and nutrients) under this set of practicesnutrients) under this set of practices

3.3. Does it meet goal (“need”)? If no, repeat with more Does it meet goal (“need”)? If no, repeat with more extensive conservation practices; if yes, write final extensive conservation practices; if yes, write final report.report.

Other Applications Other Applications Nutrient Standard in Iowa Nutrient Standard in Iowa

Improved SWAT capabilities (buffers!)Improved SWAT capabilities (buffers!) Finer spatial scale (NRI level)Finer spatial scale (NRI level) Better cost informationBetter cost information

Detailed watershed studiesDetailed watershed studies Walnut CreekWalnut Creek Sny MagillSny Magill South ForkSouth Fork

Upper Mississippi River Basin – Hypoxia Upper Mississippi River Basin – Hypoxia

The USDA Conservation Effects Assessment Project (CEAP)

Components and Reporting Scales

National assessment of conservation benefits led by NRCS supported by ARS hydrologic modeling

Watershed assessment studies (WAS) – jointly led by ARS and NRCS to provide more detailed information on conservation effects in benchmark watersheds.

ARS 12 Benchmark Watershed ARS 12 Benchmark Watershed Assessment Studies (WAS)Assessment Studies (WAS)

2003-20072003-2007

S. Fork Iowa River

Walnut Creek

Mark Twain Reservoir

U. Washita River

U. Leon River

Town Brook

St Joseph River

U. Big Walnut Creek

Yalobusha River

Little RiverGoodwin CreekBeasley Lake

• Implement a system to compile and manage Implement a system to compile and manage water, soil, management and economics data.water, soil, management and economics data.

• Measure water quality, water quantity, soil Measure water quality, water quantity, soil and ecosystem effects of conservation and ecosystem effects of conservation practices.practices.

• Calibrate watershed models and quantify Calibrate watershed models and quantify uncertainties of model predictions.uncertainties of model predictions.

• Develop and apply planning tools for selection Develop and apply planning tools for selection and placement of conservation practices.and placement of conservation practices.

• Develop and verify regional watershed models Develop and verify regional watershed models to quantify environmental effects.to quantify environmental effects.

Objectives of WASObjectives of WAS

Water Quality Measures

• Nitrogen (nitrate, total, organic)Nitrogen (nitrate, total, organic)

• Phosphorus (total, dissolved, Phosphorus (total, dissolved, available)available)

• Sediment (concentration, particle size Sediment (concentration, particle size -- -- suspended, bed)suspended, bed)

• Pathogens (Pathogens (E. ColiE. Coli))

• PesticidesPesticides

• Annual, event, and seasonal loadsAnnual, event, and seasonal loads

• TemperatureTemperature

Conservation Practice Categories Conservation Practice Categories EmphasizedEmphasized

• nutrient managementnutrient management

• pest managementpest management

• conservation buffersconservation buffers

• tillage managementtillage management

• manure managementmanure management

• drainage managementdrainage management

• channel managementchannel management

• Land ConversionLand Conversion

Conservation PracticesConservation Practices

Buffers

Drainage

Manure

Channel

S. Fork Iowa River, IA

Walnut Creek, IA

Mark Twain Reservoir, MO

Upper Washita River, OK

Goodwin Creek, MS

Yalobusha River, MS

Beasley Lake, MS

Leon River, TX

Little River, GA

Town Brook, NY

St Joseph River, IN

Upper Big Walnut Creek, OH

Nutrient

PestTilla

ge Land

Conversi

on

• What are the measurable effects of CPs on What are the measurable effects of CPs on environmental indicators at the watershed scale?environmental indicators at the watershed scale?

• How does the location of CPs affect How does the location of CPs affect environmental indicators? environmental indicators?

• What is the appropriate time scale to expect What is the appropriate time scale to expect changes in environmental effects? changes in environmental effects?

• What are the environmental effects of multiple What are the environmental effects of multiple CPs. (+, -, *, ?)CPs. (+, -, *, ?)

• What are the optimal combinations and location What are the optimal combinations and location of CPs to achieve environmental goals?of CPs to achieve environmental goals?

• What are the risks and uncertainties associated What are the risks and uncertainties associated with achieving these environmental effects?with achieving these environmental effects?

• What social and economic factors facilitate or What social and economic factors facilitate or impede implementation of CPs within impede implementation of CPs within watersheds? watersheds?

Watershed Assessment QuestionsWatershed Assessment Questions

SWAT Applications for Climate SWAT Applications for Climate ChangeChange

Variability of streamflow, sediment, and Variability of streamflow, sediment, and nutrient transport under current climate nutrient transport under current climate variabilityvariability

Changes of streamflow, sediment, and Changes of streamflow, sediment, and nutrient transport in future scenarios of nutrient transport in future scenarios of climate changeclimate change

Attribution of current streamflow variability Attribution of current streamflow variability to anthropogenic greenhouse gas to anthropogenic greenhouse gas emissionsemissions

Climate Data ResourcesClimate Data Resources

Observed climateObserved climate Reanalyzed climate (1979 - present)Reanalyzed climate (1979 - present) Future scenario climates at regional scale Future scenario climates at regional scale

[(4 GCMs/current+4GCMs/future)x5 RCMs [(4 GCMs/current+4GCMs/future)x5 RCMs = 40 future scenario climates]= 40 future scenario climates]

Pre-industrial climate at regional scalesPre-industrial climate at regional scales

Questions to be AnsweredQuestions to be Answered

Will conservation practices implemented today Will conservation practices implemented today be appropriately designed for future climates?be appropriately designed for future climates?

Can we design a fully integrated modeling Can we design a fully integrated modeling framework that couples policy options and framework that couples policy options and resulting management choices together with resulting management choices together with climate scenarios and hydrological climate scenarios and hydrological consequences to develop science-based options consequences to develop science-based options for promoting profitable but sustainable use of for promoting profitable but sustainable use of land and water resources. land and water resources.

Water Quality

PublicPolicy

Incentives

ClimateOver UMRB

Streamflow

SoilDrainage

ManagementChoices

Crop Yield

Land-use

NNR

OBS

Soil Carbon

Evaluate Sustainabilityand Profitability

SWAT

RCM

EconomicModel

CropModel

GCM

OBS

Crop Production