DESALINATION AND AQUIFER STORAGE AND RECOVERY POTENTIAL OF THE SALINE EDWARDS AQUIFER, CENTRAL TEXAS

Increased demand for water in central Texas is causing water users to look for additional sources of water. One of the potential sources of water being considered is the saline Edwards Aquifer that extends from Bell County, north of Austin, to Kinney County, west of San Antonio. Previous studies of the saline Edwards Aquifer have focused on the potential for movement of the saline/freshwater interface due to pumping of the freshwater Edwards. These studies have indicated that any impact to the interface from pumping and drought would be minimal. Studies are currently being conducted to evaluate the potential for storage of freshwater in the saline Edwards Aquifer with an aquifer storage and recovery system (ASR) and for use of the saline groundwater in desalination treatment plants. In August 2016, a multiport monitor well was installed to a depth of 1,100 ft through the entire Edwards Aquifer with 15 zones from which discrete samples can be collected and in which hydraulic conductivity tests can be conducted. Initial results of these studies indicates that just one mile east of the interface near Buda, Texas, the saline Edwards Aquifer is highly saline with values for total dissolved solids between 9,000 and 17,000 mg/L. Hydraulic conductivity values range between 0.001 and 474 ft/day indicating that the aquifer is sufficiently permeable to allow for extraction of saline groundwater and for storage of freshwater. Evaluations are also being conducted of the economic feasibility of desalination and ASR in the saline Edwards.