3. Edwards Aquifer
โข Balcones Fault Zone
โข Limestone and Artesian Aquifer
โข Aquifer responds directly to pumping or recharge
โข 4350 square miles
โข Austin, San Marcos, New Braunfels, San Antonio
โข Headwaters to San Marcos and Comal Springs
4. Edwards Aquifer cont.
โข Guadalupe River baseflow
โข Home to Endangered Species
โข Comal Springs Dryopid Beetle
โข Comal Springs Riffle Beetle
โข Fountain Darter
โข Peckโs Cave Amphipod
โข San Marcos Salamander
โข San Marcos Gambusia
โข Texas Blind Salamander
โข Texas Wild Rice
5. Demands on Edwards Aquifer
โข Municipal Water
โข Agriculture Use
โข Industrial Use
โข Recreational
โข Biological
โข Spring Flow
โข Pumping vs. Springflow
Pumping vs Springflow
6. Limitations of the Edwards Aquifer
โข 1956 Drought of Recordโ Comal Springs ceased to flow for 6 months
โข Increased demand
โข San Antonio: population of 2 million
โข Surrounding communities
โข Increased Development / Reduced Recharge
โข Drought magnifies all
โข Endangered Species Act of 1973
7. Legal Challenges
โข Sierra Club v USFWS 1991
โข Sierra Club alleged that unrestricted withdrawals from the aquifer would cause
take of Endangered Species. Courts agreed and established โtakeโ and
โjeopardyโ flow rates; water supply restrictions
โข 2012 Deadline for โContinuous Minimum Springflowsโ for the species
โข Senate Bill 1477 - 1993
โข Established EAA and set withdrawal limits