Ground-Water Quality and Structural Control in Southeastern Virginia
Investigations into the stratigraphy, structure, piezometric surfaces, and ground-water chloride concentrations of the York-James peninsula and adjacent Coastal Plain areas to the south indicate that these geologic factors display a mutual dependence. North-south e-log correlations across the area support existence of the proposed Hampton Roads fault in the vicinity of the James River. Isochlor contours trend subparallel to the James River in the York-James peninsula, and piezometric surfaces show a marked dissimilarity on either side of this river boundary. The high chloride concentrations in this area, plus the disruption of the ground-water system, imply fault control and incursions of saline waters along the Hampton Roads fault zone during times of recurrent movement. A similar situation exists near the confluence of the James River with the Chesapeake Bay, where a disrupted piezometric surface and a high chloride zone are found in conjunction with a proposed north to north-westerly trending fault zone, the Norfolk Hinge. Highest chloride concentrations, greatest disruption of the piezometric surface, and greatest stratigraphic displacement occur near the intersection of these two faults.