Municipal water needs in Travis County, selected water-policy shortcomings, and water conversation...
-
Upload
brittany-jennings -
Category
Documents
-
view
213 -
download
0
Transcript of Municipal water needs in Travis County, selected water-policy shortcomings, and water conversation...
Municipal water needs in Travis Municipal water needs in Travis County, selected water-policy County, selected water-policy
shortcomings, and water shortcomings, and water conversation measuresconversation measures
Raymond Slade, Jr., PH
Certified Professional Hydrologist
Slide show organizationSlide show organization• Drought Drought • Texas Water PlanTexas Water Plan• Municipal water supply needs in Travis CountyMunicipal water supply needs in Travis County• Selected water policy shortcomings in TexasSelected water policy shortcomings in Texas• Effective water conservation measuresEffective water conservation measures
Google “Texas flood”…Google “Texas flood”…
DefinitionsDefinitionsWhat Texans know about waterWhat Texans know about water
You might get a TV meteorologist defining drought as an annual rainfall deficit
Father Guido Sarducci Vatican Weatherman, SNL
It’s gonna rain or…
Typical drought cycleTypical drought cycle
From TWDB
Start here
agriculture agriculture
StreamflowReservoirs & Groundwater
StreamflowReservoirs &Groundwater
Decreasing numbers represent greater drought intensity
Green—wetter than normalGold – drier than normalEdwards Plateau
Through March 18, 2015
Assessment of current droughtAssessment of current drought
Hydrologic drought index
1952-57 drought more intense than current drought
Indicates substantial flooding after severe drought
Source and fate (water budget)
Data values in million gallons per day
90%
8%
2%
99%1% <1%
% of inflow % of outflow
consumption
border flow
Why Texas droughts occur fast and are intenseWhy Texas droughts occur fast and are intense
2 reasons
99% of source water to Texas from rainfall but about 90% of that lost to evapotranspiration thus only 10 % of rain available for use
Texas Water Plan 2012Texas Water Plan 2012 Purpose of Plan
Estimate current and future water needs (shortages) and identify water management strategies and associated costs to meet future needs.
http://www.twdb.state.tx.us/wrpi/swp/swp.asp
Based on
Data and analyses of current and future population, water use, and water availability (every 10 years from 2010 to 2060)
Severe drought conditions (water demand at maximum and supply at minimum)
6 water use types: i.e., municipal (urban & rural), irrigation, livestock, manufacturing, mining, and steam electric)
Texas Water Development Board
Existing water supplies - the amount of water that can be produced with current permits, current contracts, and existing infrastructure during severe drought (1950s drought).
Water Demand Projections - Quantity of water projected to meet the overall necessities of an area in a specific future year.
Water supply needs (shortage) - projected water demands in excess of existing supplies that would be legally and physically available during a severe record (1950s drought).
Water management strategies - projects and associated amount of water designed to meet needs for additional water supplies during drought. Proposition 6 money to fund strategies.
Definitions of water category terms in the Definitions of water category terms in the Texas Water PlanTexas Water Plan
Water Supplies from the Water PlanWater Supplies from the Water Planbased on 1950s drought conditionsbased on 1950s drought conditions
200-year drought 50-year droughts
20-year drought1950s drought compared to Texas droughts from past 2000 years based
on tree ring analyses
In Travis CountyIn Travis County
Current and future municipal water needsCurrent and future municipal water needs
Municipal (urban and rural) water needs (shortages) Municipal (urban and rural) water needs (shortages) for Travis County for Travis County (based on 1950s drought)(based on 1950s drought)
2010 “Severe” drought conditions 2030 “Severe” drought conditions
28,000 peopleNeed volume = 16% of Lake Austin
105,000 peopleNeed volume = 60% of Lake Austin
2060 “Severe” drought conditions2060 “Severe” drought conditions (based on 1950s drought)(based on 1950s drought)
1.78 million people; Need volume = 3.7 times greater than Lake Austin
Need(shortage)
Why is inflow being reduced to Lake Buchanan19 upstream major reservoirs—some less than 5 to10% full
39% decrease in inflow
Selected water policy shortcomings in TexasSelected water policy shortcomings in Texas(pertinent to Austin water sources )(pertinent to Austin water sources )
Lack of proper regulation of groundwater pumpage
• June 1904: Texas Supreme Court laid the foundation of Texas groundwater law: the rule of free capture. “Because the existence, origin, movement, and course of such waters, … are so secret, occult, and concealed that an attempt to administer any set of legal rules …would be impossible.
• Rule of free capture: Landowner can pump as much groundwater as wanted from beneath their land, regardless of the effects on neighboring wells, so long as they are not “wasting” the water. (Based on oil and gas reserves—groundwater moves). Exception—jurisdiction of Groundwater Conservation Districts. Most of Travis County not in a district.
• In Edwards Aquifer Authority vs. Day (2012), Texas Supreme Court rules that Groundwater districts may impose “reasonable” limits on pumping from wells within their boundaries, but a landowner may sue the district for compensation if limits are excessive.
• In Edwards Aquifer Authority vs. Bragg Pecan Farm (2013), the Texas Fourth Court of Appeals ruled that the Edwards Aquifer Authority owes landowners money for “taking” their groundwater by limiting pumping.
Areas in white not protected by a Groundwater Conservation District
Water developer can obtain right from landowner to pump unlimited water from areas not protected by a GCD
Proposition 6Proposition 6
• What does Proposition 6 do?• Transfers $2 billion from the State’s Economic Stabilization
Fund to the State Water Implementation Fund
• How will the money be used?
• Support projects identified in the State Water Plan. The TWDB “shall undertake to apply” 10% of the funds for rural political subdivisions and agricultural water conservation and 20% for water conservation and reuse. The money may be used for low-interest loans, and other methods of financial assistance for public entities developing and managing water supplies.
Lack of regulatory water conservation measures
Five water conservation measuresFive water conservation measures1. Fix leaking pipes and canals: Water conveyance losses in
Texas are estimated to be about 600,000 acre feet per year, a value equal to the existing Statewide municipal water need (shortage).
2. Use urban Xeriscape, less water-thirsty vegetation: About one-half of residential water use is for lawns.
3. Remove thirsty rural phreatophytes: For example, the water loss due to transpiration from tamarix (salt cedar) and mesquite in the main stream flood plain in the Colorado River in west Texas is equivalent to the long-term mean flow in the river--136 million gallons per day.
90% of Tx water lost to ET
4. Residential greywater systems: Use of greywater (water from sinks, tubs, and washing machines) to irrigate lawns would cut residential water use in half.
Rainwater harvesting5. Rainwater harvesting5. Rainwater harvesting
Texas water sourceFlow from other states
PrecipitationFate of source water
Evaporation and transpiration
Runoff to streams, lakes, and groundwater
1% 99%90% 10%
Residential water supply from surface water or groundwater
Summary: Each house using water from surface water or groundwater uses the same amount of source water as 10 houses using rainwater harvesting
Residential water supply from rainwater harvesting
90 gallons of source water lost for each 10 gallons of water used
Almost all source water used—no lost water