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Groundwater & Surface Water Crossroads Bastrop County ▲ Milam & Robertson Counties Where the Colorado & Brazos Rivers Intersect the Carrizo-Wilcox Aquifer.

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Presentation on theme: "Groundwater & Surface Water Crossroads Bastrop County ▲ Milam & Robertson Counties Where the Colorado & Brazos Rivers Intersect the Carrizo-Wilcox Aquifer."— Presentation transcript:

1 Groundwater & Surface Water Crossroads Bastrop County ▲ Milam & Robertson Counties Where the Colorado & Brazos Rivers Intersect the Carrizo-Wilcox Aquifer Groundwater Management Area 12 October 30, 2008

2 Environmental-Stewardship.org Steve Box Executive Director, MS Environmental Science & Ecology Environmental Stewardship A Texas nonprofit 501(c)(3) public charity Our purposes: ▲Protect & enhance natural resources to meet current and future needs of the environment and humans. ▲Use scientific information to restore & sustain ecological systems. ▲Provide education & outreach to encourage public stewardship of natural resources.

3 Vision Endorse the Environmental Goal of Opportunity Bastrop County: ▲Retain and enhance the rural character of Bastrop County while encouraging growth that is in balance with human and environmental needs today and in the future. Adopted by Bastrop County Commissioners Court December 10, 2007

4 Vision Embrace the values of the citizens of the lower Colorado River basin related to water supply: 1.Clean water, protection of environment 2.Recreation & lifestyle 3.Availability 4.High quality water supply 5.Management of growth 6.Affordability 7.Jobs and economic growth LCRA Press Release October 24, 2008

5 Vision Applaud the Texas State Legislature in recognizing the value of environmental flows by enacting Senate Bill 3. ▲ SECTION 1.06. (b) Maintaining the biological soundness of the state's rivers, lakes, bays, and estuaries is of great importance to the public's economic health and general well-being. The legislature encourages voluntary water and land stewardship to benefit the water in the state. (c) The legislature has expressly required the commission while balancing all other public interests to consider and, to the extent practicable, provide for the freshwater inflows and instream flows necessary to maintain the viability of the state's streams, rivers, and bay and estuary systems in the commission's regular granting of permits for the use of state waters ▲ "Environmental flow regime" means a schedule of flow quantities that reflects seasonal and yearly fluctuations that typically would vary geographically, by specific location in a watershed, and that are shown to be adequate to support a sound ecological environment and to maintain the productivity, extent, and persistence of key aquatic habitats in and along the affected water bodies. ▲ Establishes an Environmental Flows Stakeholder Group for the Colorado and Lavaca Rivers and Matagorda and Lavaca Bays to be appointed in the Spring of 2009. Passed by 80 th Session of the Texas State Legislature Signed into Law June 16, 2007

6 Vision Manage the groundwater resources underlying GMA-12 in a manner that balances human and environmental needs both now and into the future. ▲ Ensure a publicly informed process ▲ Provide for the needs of each County ▲ Provide base-flows for the rivers, streams, & springs ▲ Maximize recharge ▲ Establish “canaries” to warn of imbalances ▲ Provide export to the extent possible

7 Outline Lessons from the “Credit Crisis” Current Conditions The Regional Challenge A Platform for Response

8 Lessons from the “Credit Crisis” Live within our means Ensure that the infrastructure is sound Have checks and balances In Groundwater Terms: Use only the water we can replace Protect the ecological integrity of the system Establish key indicators of system health

9 Current Condition Carrizo-Wilcox Aquifer charges water into the Colorado and Brazos Rivers, streams, and springs Net Flow Aquifer  Rivers

10 Currently the Carrizo-Wilcox Charges the Rivers Charge to Aquifer (Recharge) Charge to River (base-flow) Colorado River Brazos River Under Current Conditions the Carrizo-Wilcox Aquifer Charges Water into the Colorado and Brazos Rivers (Base-flow) Currently “Gaining” Rivers

11 Recorded Springs in GMA-12 We know there are many more in Bastrop County.

12 The Regional Challenge Regional Planning vs. Groundwater Management Reversal in Flow Aquifer  Rivers

13 Water Planning Regions Region G Brazos Regional WPG Region K Lower Colorado Region WPG

14 Region G Water Plan CountyAvailable Groundwater (Estimated) * (ac-ft/yr) Groundwater Recharged (Estimated) ** (ac-ft/yr) Milam and 90,00044,900 Burleson Brazos and 90,00019,000 Robertson Lee 45,000 (protested) 7,500 TOTAL225,000 (1 football field 87 mi high) 71,400 (32%) Difference(153,600 ac-ft/yr) * Region G Water Plan (Table 3.4-4) 1 football field 29 miles high ** Post Oak Savannah GAM Run 05-05; Brazos Valley GCD Mgt Plan; Lost Pines GCD Mgt Plan

15 Acre-Feet/Year Acre-Feet/Year of water –Acre-Foot = 1 ft of water over one acre of land About 1 Football Field 1 ft deep in water –Abbreviation = ac-ft/yr ac-ft/yr = gallons –1= 325,851 gallons –1= 326 thousand gallons –1,000 = 326 million gallons –10,000= 3.3 billion gallons –100,000= 36 billion gallons About 1 Football Field 19 miles high in water

16 Region K Water Plan 1.2.4.2 Threats Due to Water Quantity Issues The relationships that currently exist between surface and groundwater may also change. “Simulations indicate that the Colorado River, which currently gains water from the Carrizo-Wilcox aquifer, may begin to lose water to the aquifer by the year 2050”. (page 1-44)

17 Reverse Ecology -- Rivers Charge Carrizo-Wilcox Charge to Aquifer (Recharge) Charge to River (base-flow) Groundwater Export Colorado River Brazos River Under Over-Pumped Conditions the Colorado and Brazos Rivers Charge Water into the Carrizo- Wilcox Aquifer (Recharge) With Over-Pumping they become “Losing” Rivers

18 A Platform for Response DFC based on Water Budget plus Springflow and river base-flow Retain Current Flow Aquifer  Rivers

19 A Groundwater Perspective on Surface Water Resources for GMA12 Dan Opdyke, PhD, PE Water Resources Branch May 10, 2007

20 Streamflows are gauged in many locations and often have a long period of record. TPWD Proposed DFC Metric: Streamflows Streamflows have a direct impact on the environment. Surface water rights have been authorized contingent on the historical streamflow record Streamflows are a highly visible characteristic of the Texas landscape Opdyke to GMA-12, May 10, 2007

21 Importance of Springs and Baseflows Springs –Support unique aquatic environments, including rare species –Serve as a barometer of local aquifer conditions –Relatively inexpensive means of monitoring groundwater –Provide important baseflows to rivers Baseflows –Dependent on aquifer discharge –Important component of natural flow regime –Support habitats during dry periods Opdyke to GMA-12, May 10, 2007

22 GMA-12 Groundwater Contribution to Surface Water (GW SW) Opdyke to GMA-12, May 10, 2007

23 GMA-12 Groundwater Contribution to Surface Water (GW  SW) TPWD estimated that the Carrizo-Wilcox, Queen City and Sparta Aquifers in GMA-12 region will contribute 128 cfs less flow to surface water bodies in 2060 as compared to 2002 (2007 estimate) 128 cfs ≈ 93,000 ac-ft/yr A column of water the size of a football field ~ 18 miles high Latest estimates are 136 cfs (per Opdyke, 2008) Opdyke to GMA-12, May 10, 2007

24 TPWD Recommendations (in order of increasing difficulty) Consider impacts to surface water during DFC deliberations Include quantitative impacts to surface water in DFC definitions Improve the GAMs in their representation of Groundwater/Surface water interaction Opdyke to GMA-12, May 10, 2007

25 Environmental Stewardship On behalf of our rivers, streams, & springs Requests: ▲ GMA-12 heed TPWD recommendation & 80 th Legislature’s Guidance ▲ Include base-flows to the Colorado & Brazos rivers in DFC –Establish quantitative measures using USGS Acoustic Doppler Current Profile (ADCP) technology ▲ Include spring flow in DFC –Voluntary registration & monitoring of springs –“Canaries” to act as early warning of imbalances ▲ Link pumping limits/remedial actions to base-flows ▲ Limit pumping to rates that are less than recharge ▲ Encourage protection of recharge land ▲ Encourage rainwater collection & recharge projects ▲ Encourage conservation by all users (counties & export)

26 It’s GMA-12’s Responsibility to the Citizens of our Region To establish Desired Future Conditions (DFC) for the aquifers in our region that protect the groundwater, surface water, and environmental resource of the area. DFC’s that: –Protect the Aquifers rivers & streams Springs Surface features (Trees, etc.) –Balance Pumping and Recharge –Provide needs of Counties Export where possible

27 Steve Box Environmental-Stewardship.org 512-300-6609 Steve.Box@att.net


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