A recharge-discharge water budget and evaluation of water budgets for the Edwards Aquifer associated with Barton Springs

Abstract

The Barton Springs segment of the Edwards Aquifer represents a small, relatively independent part of the aquifer. Data for the sources of recharge and especially for discharge from the aquifer are well documented. Based on a 6-year water budget of surface recharge and surface discharge, the volumes match within 5%, which is within the potential error limits of the recharge and discharge values. Recharge volumes include increased runoff due to urbanization in the recharge area. A previous water budget based on an earlier period also displayed a balance between recharge and discharge volumes. Both budgets are based on slightly "wetter" than long-term mean recharge and discharge conditions, thus subsurface recharge from south of the aquifer segment, which is documented to occur during dry conditions, was an insignificant source of recharge during the budget periods. The recharge volumes are based on data from streamflow gaging stations operated by the U.S. Geological Survey. However, one of the stations (Bear Creek near Brodie Lane) was discontinued in 2010; this station is needed to calculate recharge volumes on Bear Creek and Little Bear Creek. Because of the discontinuance of the station, any calculations of recharge volumes after 2010 would contain substantial potential error.