Potentiometric surface of the lower Patapsco Aquifer in southern Maryland, September 1994

A map showing the potentiometric surface of the lower Patapsco aquifer in the Patapsco Formation of Cretaceous age in southern Maryland during September 1994 was prepared from water levels measured in 56 wells. The potentiometric surface was at least 104 feet above sea level near the northwestern boundary and outcrop area of the aquifer in a topographically high area of Prince Georges County, and at least 89 feet above sea level in a similar setting in Anne Arundel County. From these high areas, the potentiometric surface declined to the south and southeast toward large well fields at Crofton, Severndle, Arnold, Annapolis, Waldorf, La Plata, Indian Head, and Morgantown. The ground-water levels reached 20 feet below sea level at Crofton, 80 feet below sea level at Severndale, 25 feet below sea level at Arnold, more than 10 feet below sea level near Annapolis, more than 130 feet below sea level in the Waldorf area, more than 100 feet below sea level at La Plata an Indian Head, an nearly 80 feet below sea level at the Morgantown powerplant.