Potentiometric surface of the upper Patapsco aquifer in southern Maryland, September 1997

This report presents a map showing the potentiometric surface of the Upper Patapsco aquifer in the Patapsco Formation of Cretaceous age in Southern Maryland during September 1997. The map was prepared from water-level measurements in 42 wells. The potentiometric surface was 122 feet above sea level near the northern boundary and outcrop area of the aquifer in a topographically high area of Anne Arundel County, and 57 feet above sea level in a similar setting in Prince Georges County. From these high areas, the potentiometric surface declined to the southeast toward large well fields in the Annapolis area and Arnold and from all directions toward a cone of depression southwest of Waldorf. Ground-water levels reached 20 feet below sea level in the Annapolis area, 28 feet below sea level at Arnold, and 118 feet below sea level southwest of Waldorf.