GTA provided remote sensing, geophysics, and hydrogeologic services to evaluate and select locations for groundwater production well drilling. GTA performed fracture trace analysis of the site vicinity to evaluate areas of the site where zones of subsurface rock fracturing may be present. Potential fracture zones were “ground-truthed” via site reconnaissance. Based on the results of the fracture trace analysis, reconnaissance and review of published geologic literature, transects throughout the site were selected for performance of electrical resistivity and very low frequency (VLF) surveys.
Electrical resistivity and VLF surveys were performed and the data were analyzed in conjunction with fracture trace analysis results to identify potential zones of relatively intensive fracturing of water-bearing rocks. Zones that were identified were selected for future test well drilling. The geophysical methods applied at the site facilitated analysis of subsurface conditions extending downward to 200 feet or more below the existing ground surface.