The Edwards Aquifer is currently the subject of much public attention as policy makers and politicians attempt to determine optimal pumping strategies.
Little information is currently available about the characteristics of the bad water zone.
This paper summarizes and interprets the results of data from numerous state, federal and university studies dealing with the geology, hydrogeology and chemistry of the Edwards Aquifer. In the far western part of the aquifer in Kinney and Val Verde counties, the dissolved components in the bad water zone are mainly calcium and sulfate which apparently resulted from the dissolving of gypsum. From southwestern Uvalde County to southern Bexar County, the bad watercontains calcium, magnesium, and sulfate, but also has significant amounts of sodium and chloride. Between northern BexarCounty and Travis County, sodium and chloride are the dominant constituents, but significant amounts of calcium, magnesium, and sulfate are also present. In this region, faults restrict the movement of bad water into the aquifer.