HYDROGEOLOGICAL ASSESSMENT ON TONKAWA FALLS, CRAWFORD, TEXAS

Tonkawa Falls City Park is a recreational park located in the City of Crawford, in Central Texas. The main park attraction is the water fall and plunge pool fed by baseflow from Tonk Creek and springs from the Edwards and Georgetown formations which crop out in the stream valley. The Edwards and Georgetown formations are considered part of the Edwards aquifer farther south but not recognized as an official State aquifer at this location. Although the park is well-attended in the early summer, the popularity wanes in the late summer when flows decrease. The purpose of this project was to assess the hydrogeological setting and the potential for augmented flows during the dry season to increase park visitation. Discharge was measured using a variety of methods during different flow conditions using velocity meters, flumes and other methods. The discharge measurements were coupled with limited water quality tests (T, pH, Ec, and DO) for several months during higher and lower flow conditions. The geologic framework and hydrogeological setting were described to aid in understanding the potential for using wells and groundwater for augmented flow during the dry season. In addition, to the hydrogeological science information, data potentially needed by the local groundwater conservation district were provided to the city. Results indicate it may be difficult to augment flow throughout the year but that it may be possible to manage flows to increase the duration of attractive flows and thereby increase park visitation.