THE EDWARDS AQUIFER AND ITS UNIQUE ECOSYSTEM – POTENTIAL THREATS FROM GROUNDWATER MANAGEMENT

The Balcones Fault Zone Edwards Aquifer is a complex groundwater system that supports one of Earth's most diverse groundwater ecosystems. In excess of 40 species inhabit this mostly confined karst aquifer. Most of the described species are macroinvertebrates, and at the top of the food chain in this system are some unique, troglobitic aquatic vertebrates, including Federal Endangered species. The vertebrates include salamanders, and two species of blind catfish. They have been found in wells and caves, some at depths of 2000 + feet below the surface.

The energy dynamics of this system are not well studied. The hypotheses in this presentation indicate two types of energy flow. New studies are beginning to provide some insight into how the system may work.

Proposals to augment groundwater, by various means, will be discussed. Some advocate use of recirculation to maintain springs; some would use aquifer storage and recovery. The characteristics of the water in the various schemes would not necessarily be the same as the aquifer water. The organisms that inhabit the aquifer have evolved in the system with particular water characteristics, it is not understood what impacts would occur from placing water with different characteristics in the Edwards.

This aquifer was the first listed as a, “Sole Source Aquifer”. It provides water to a population in excess of 1.4 million people. Our region is now experiencing a drought that causes water purveyors to look at all types of alternatives for supplying water.