Maps showing lithofacies and inferred sub-surface distribution of channel-fill sand aquifers in the Potomac Group in Fairfax County, Virginia

Geological Survey research 1978

“…The Coastal Plain and Triassic and Jurassic Low land were selected as the most favorable areas to explore for supplemental public water supplies in Fairfax County, Virginia, based on preliminary re sults of the Fairfax County environmental geology study (Johnston and Froelich, 1977;Johnston and Larson, 1977). The Fairfax County Board of Super visors, acting on these preliminary results, recom mended-and the Fairfax County Water Authority agreed to fund-an exploratory drilling and aquifer test program.…”

“…In the Coastal Plain, high transmissivity aquifers in the Cretaceous Potomac Group are relatively nar row, sinuous sand deposits that fill paleochannels (Johnston and Froelich, 1977). As these sand bodies are for the most part poorly defined at depth (aver aging 120 m), the chief problem is to locate thick sand sections and to determine their areal extent and hydraulic characteristics.…”

Potentiometric surface maps and water-level change map, 1960-76, for the lower aquifer of the Cretaceous Potomac Group in Fairfax County, Virginia

“…, a map depicting the altitude of base and thickness of the Potomac Group (Larson and Froelich, 1977) and maps showing lithofacies and sub-surface distribution of sand aquifers (Johnston and Froelich, 1977). Future maps in this series will show transmissivity of the lower aquifer, chemical quality of ground-water, and areas of high ground-water potential.…”