Technical Reports Document Library

The average estimated annual groundwater recharge to the Edwards aquifer in the San Antonio area from 1934 through 1995 was 674,200 acre-feet. Recharge in 1995 was 531,300 acre-feet, which was well below the regional average. The lowest annual recharge of 43,700 acre-feet occurred in 1956 and the highest annual recharge of 2,486,000 acre-feet occurred in 1992.

The estimated annual discharge from the Edwards aquifer through wells and springs in 1995 was 761,000 acre-feet. The lowest annual discharge through wells and springs was 388,800 acre-feet which occurred in 1955. Water level data for wells during 1995 reflected a general decrease in Edwards aquifer groundwater in storage during the year.

In 1995, the Edwards Aquifer Authority collected water quality samples from 58 wells, three springs, and seven streams and rivers. These samples were analyzed for 74 constituents and parameters which included common organic constituents, nutrients, dissolved organic carbon, metals and VOCs. Laboratory analyses indicated that samples from 33 wells contained detectable metal concentrations. These concentrations were well below the MCLs for those
constituents. No detectable concentrations of pesticides or VOCs were measured in the wells sampled in 1995.

Results of the Authority’s 1995 water quality monitoring program illustrate the continued excellent quality of water in the Edwards aquifer.