- Edwards Aquifer
The Edwards Aquifer is one of the most prolific artesian
aquifer s in the world. Located on the eastern edge ofEdwards Plateau in theU.S. state ofTexas , it discharges about 900,000 acre feet (1.1 km³) of water a year and directly serves about two million people. [http://www.edwardsaquifer.net/data.html] The Edwards Aquifer is also home to several unique and endangered species.Geography
The aquifer's recharge zone, where surface water enters the aquifer, follows the
Balcones Fault line, from Brackettville (roughly along U.S. Highway 90), through San Antonio, and north to Austin (roughly along Interstate 35). Its contributing zone, where shed water is transported near the surface to the recharge zone, extends about 40 miles (64 km) north of the recharge zone at the west end, and tapers to end at a point in the east. The artesian zone, where water springs from wells naturally due to the higher elevation of the recharge zone, extends 10-20 miles (16-32 km) south on the west end to only a few miles south on the east end. Across the eastern half of the aquifer, the recharge and artesian zones occupy common area.Economy
The plentiful water provided by rivers fed from the Edwards Aquifer is the primary reason Spanish
missionaries were able to establish so many missions, like theAlamo Mission in San Antonio . Later, immigrants found theTexas Hill Country welcoming because of the food, energy, and water provided by these rivers. Without this supply in thearid plateau, early colonization would have been far more difficult. Cities like San Antonio, New Braunfels, and San Marcos have been able to support large populations without the need to develop surface water resources. Farmers and ranchers south of the aquifer benefit greatly or entirely from theirrigation possible from these rivers.Ecology
The Edwards Aquifer is home to several unique species, including the
widemouth blindcat ,Texas blind salamander ,helotes mold beetle , therobber baron cave harvestman , and therobber baron cave spider . These species actually live in the caves, and are either completely without eyes or their eyes are so underdeveloped that they are essentially eyeless. The springs fed from the aquifer are also home to many unique species, such as theFountain Darter ,San Marcos Gambusia (which might already be extinct), and theSan Marcos salamander .Texas Wild Rice is also found only in the upperSan Marcos River .ee also
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Edwards Plateau
*Balcones Fault
*San Marcos River
*Comal River
*Guadalupe River
*Central Texas
*San Antonio Water System
*Texas Hill Country
*Texas Blind Salamander External links
* [http://edwardsaquifer.org/ Edwards Aquifer Authority]
* [http://www.tsha.utexas.edu/handbook/online/articles/EE/mwe1.html Handbook of Texas Online, s.v. "EDWARDS UNDERGROUND WATER DISTRICT,"]
* [http://www.edwardsaquifer.net/ Edwards Aquifer Home Page, Gregg Eckhardt]
* [http://www.edwardsaquifer.net/species.html Endangered Species of the Edwards Aquifer]
* [http://www.sosalliance.org/eaproplan.shtml Save Our Springs Alliance - Edwards Aquifer Protection Plan]
* [http://www.aquiferalliance.org/ Greater Edwards Aquifer Alliance]
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