DETECTION OF SHALLOW KARST FEATURES WITH GEOPHYSICAL TECHNIQUES: GROUND TRUTHING THE RESULTS

Shallow karst features in the Edwards Plateau are often indicative of infiltration pathways that enable recharge of the Edwards aquifer. When evaluating a landscape for recharge features, geophysical techniques can be utilized to determine the approximate location of shallow voids that may link to additional solution pathways. This paper will show examples of features in the San Antonio area imaged with either ground penetrating radar (GPR), resistivity, or in some cases both. The data from the geophysical surveys is then compared with ground truthing methods to determine the accuracy of the scans in determining feature size. Features examined include voids in the Edwards Limestone and the Glen Rose Limestone.