An Evaluation of Some Geophysical Methods for Water Exploration in the Piedmont Area

Abstract

AbstractThe Piedmont is underlain by igneous and metamorphic rocks, from which it is difficult to locate quantities of ground water adequate for municipal and industrial purposes. Ground‐water occurrence and movement in the Piedmont is controlled by topography, recharge and discharge, rock type, fracture systems, and type and thickness of saprolite.Approximately 12 square miles in the Heflin area, Cleburne County, Alabama, were included in this study. Fractures within bedrock are the most effective avenues for ground‐water movement in this area, but domestic supplies can be produced from saprolite and alluvium overlying bedrock. Thick saprolite contributes to bedrock‐fracture production by absorbing water from streams and rainfall and releasing it slowly to underlying fractures.Seismic methods were used with geologic, hydrologie and topographic data to locate and define favorable areas for drilling. As shown on the seismic sections, faults or fracture systems appear to correlate with depressions on bedrock surfaces associated with thick saprolite zones. Seismic data indicate twenty‐five prospective areas for test drilling.Resistivity data were used to confirm seismic depth to bedrock, and to locate gravelly zones in buried stream channels. Some of the buried alluvium is thick enough to be considered a potential aquifer.Twenty‐five prospective areas are indicated by geophysical work in the Heflin area. A proposal to drill 10 wells to evaluate the most promising of these areas is presently being considered.