Potentiometric Surface of the Lower Patapsco Aquifer in Southern Maryland, September 2001

This report presents a map showing the potentiometric surface of the Lower Patapsco aquifer in the Patapsco Formation of Cretaceous age in Southern Maryland during September 2001. The map is based on water-level measurements in 65 wells. The potentiometric surface was as high as 110 feet above sea level near the northwestern boundary and outcrop area of the aquifer in northern Anne Arundel County. From this area, the potentiometric surface declined towards large well fields at Severndale, Arnold, and Annapolis. The ground-water levels declined to 78 feet below sea level at Severndale, 38 feet below sea level at Arnold, and 31 feet below sea level a few miles west of Annapolis. There was also a cone of depression covering a large area in Charles County that includes Waldorf, LaPlata, Indian Head, and the Morgantown power plant. The ground-water levels were as low as 173 feet below sea level at Waldorf, 126 feet below sea level at LaPlata, 112 feet below sea level at Indian Head, and 92 feet below sea level at the Morgantown power plant.