Potentiometric surface of the lower Patapsco Aquifer in southern Maryland, September 1991

A map showing the potentiometric surface of the lower Patapsco aquifer in the Patapsco Formation of Cretaceous age in southern Maryland during September 1991 was prepared from water levels measured in 53 wells. The potentiometric surface was at least 125 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 87 ft 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 Severndale, Annapolis, Waldorf, La Plata, Indian Head, and Morgantown.