Jim Brasher – General Manager, Colorado County Groundwater Conservation District January 25, 2011 – LCRA Regional Council Meeting

Outline Description of Aquifer Groundwater Usage Future Groundwater Usage

Major Aquifers of Texas

Hydrostratigraphy Gulf Coast Aquifer 2 mill yrs ago.1 mill yrs ago 7 mill yrs ago 26 mill yrs ago

Hydrologic Cross-Section

Groundwater Management Areas

GMA 15

Computer Simulations of the Gulf Coast Aquifer

3-D Conceptual Model

GAM Runs: Chicot Aquifer Pumpage Comparison

Simulation Results: Chicot Aq uifer

Evangeline Chicot Jasper Pumpage versus Water Level Change

Chicot Evangeline Pumpage versus Water Level Change

Evangeline Chicot Pumpage versus Water Level Change

Summary of Gulf Coast Aquifer Composed of Chicot, Evangeline and Jasper Aquifers (along with Burkeville Confining Unit) Chicot is best and Jasper is poorest quality Aquifers dip and thicken from NW to SE Computer simulations can project aquifer conditions based on pumpage assumptions at future points in time

Types of Groundwater Usage Municipal or Public Supply Domestic Livestock Commercial Irrigation Mining

Irrigation

Mining

Colorado County Groundwater Usage

Ave water level of index wells (CBGCD)

Future Water Usage Up until now: High availability of Colorado River water for irrigation Abundant groundwater in most of the county No accurate estimate of groundwater usage or availability – plenty of water No regulation needed

Region K Water Plan

County Bastrop1,6101,4071,2261, Blanco Burnet Colorado200,822192,465184,380176,555168,946161,663 Fayette Gillespie2,0392,0131,9871,9601,9361,912 Hays (p)11 Llano Matagorda193,048186,072179,353172,916166,722160,750 Mills2,9362,8722,8102,7492,6892,631 San Saba3,2403,1363,0352,9372,8412,749 Travis1,2241, Wharton (p)191,241176,441170,127164,044158,177135,911 Williamson (p) TOTAL589,705567,272545,634524,809504,695468,763 Lower Colorado Regional Water Planning Group (Region K) – July 2010 (p) – denotes that only the portion of the county in Region K was considered Projections of Irrigation Usage (Surface and Groundwater)

County Bastrop5,0335,0355, Blanco Burnet1,9562,0492,0982,1452,1902,235 Colorado20,80421,19721,41621,62321,82121,996 Fayette42 Gillespie Hays (p) Llano Matagorda Mills San Saba163 Travis1,5311,6491,7271,8041,8801,935 Wharton (p) Williamson (p) TOTAL30,62031,25231,61326,96427,30427,598 Lower Colorado Regional Water Planning Group (Region K) – July 2010 (p) – denotes that only the portion of the county in Region K was considered Projections of Mining Usage (Surface and Groundwater)

County Bastrop13,27518,62022,96430,04035,86043,208 Blanco1,4671,7121,9472,1432,3602,626 Burnet8,99011,43714,16616,86718,62620,550 Colorado3,1553,2923,3283,2593,3203,409 Fayette3,8904,4174,8795,2445,7516,495 Gillespie4,7495,3985,6465,5765,541 Hays (p)7,20210,65613,44616,26619,74222,498 Llano5,7226,2356,4466,6476,8757,139 Matagorda5,5905,8305,9065,8835,831 Mills1,0101,0701,0931,0531,0861,104 San Saba1,2991,3161,3281,3391,3311,336 Travis199,677237,014274,610308,229342,865369,723 Wharton (p)3,7763,8803,9103,8803,8423,806 Williamson (p)8,84111,09513,76116,62519,74323,082 TOTAL268,643321,972373,430423,051472,778516,348 Lower Colorado Regional Water Planning Group (Region K) – July 2010 (p) – denotes that only the portion of the county in Region K was considered Projections of Municipal Usage (Surface and Groundwater)

County Bastrop13,27518,62022,96430,04035,86043,208 Blanco1,4671,7121,9472,1432,3602,626 Burnet8,99011,43714,16616,86718,62620,550 Colorado3,1553,2923,3283,2593,3203,409 Fayette3,8904,4174,8795,2445,7516,495 Gillespie4,7495,3985,6465,5765,541 Hays (p)7,20210,65613,44616,26619,74222,498 Llano5,7226,2356,4466,6476,8757,139 Matagorda5,5905,8305,9065,8835,831 Mills1,0101,0701,0931,0531,0861,104 San Saba1,2991,3161,3281,3391,3311,336 Travis199,677237,014274,610308,229342,865369,723 Wharton (p)3,7763,8803,9103,8803,8423,806 Williamson (p)8,84111,09513,76116,62519,74323,082 TOTAL268,643321,972373,430423,051472,778516,348 Lower Colorado Regional Water Planning Group (Region K) – July 2010 (p) – denotes that only the portion of the county in Region K was considered Projections of Municipal Usage (Surface and Groundwater)

Future Water Use Projections Currently a shortage in some major urban areas such as San Antonio Projected Population of Texas expected to increase by 80% in the next 50 years State Water Management Plan prescribes how LCRA will allocate water during supply shortages Plan directs curtailment of interruptible water supplies so that firm water users are protected In August of 2009, plans were developed to totally cut interruptible water supply to rice farmers Likelihood of interruptible supply of Colorado River water being maintained is low

Future Water Use Projections Locally, project only small population increases, but… Colorado, Wharton and Matagorda Counties will be viewed as prime areas to exploit for transport of water to urban areas! LCRA-SAWS Project was an example Project underway to transport water from Gonzales County to San Antonio

Future Groundwater Usage Up until now: High availability of Colorado River water for irrigation Abundant groundwater in most of the county No accurate estimate of groundwater usage or availability – plenty of water No regulation needed What’s in store for the future: Dramatic population increases will dictate water needs Surface water availability from the Colorado River will likely be restricted Projections of rice production and irrigation to decrease

Future Groundwater Usage Water will increasingly be treated as a commodity Anyone who can deliver water to urban areas could be well compensated (i.e. conducive to water marketers) Result: The days of no regulation of groundwater are gone! Local control or state control?

Questions?

Geological Interpretations

Water Management Strategies

Evangeline Chicot Evangeline Chicot Jasper Evangeline Chicot Pumpage versus Water Level Change

Colorado County Rice

3-Dimensional Computer Simulation

Outcrop Map in Computer Simulation

Approximate Chicot Thickness