Potentiometric surface of the Lower Patapsco Aquifer in southern Maryland, September 2003

This report presents a map showing the potentiometric surface of the Lower Patapsco aquifer in the Patapsco Formation of Lower Cretaceous age in Southern Maryland during September 2003. The map is based on water-level measurements in 66 wells. The highest measured water level was 112 feet above sea level near the northwestern boundary and outcrop area of the aquifer in northern Prince Georges County. From this area, the potentiometric surface declined towards well fields at Severndale, Arnold, and Annapolis. The measured ground-water levels were 86 feet below sea level at Severndale, 41 feet below sea level at Arnold, and 39 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 powerplant. The ground-water levels measured were as low as 165 feet below sea level at Waldorf, 135 feet below sea level at LaPlata, 114 feet below sea level at Indian Head, and 92 feet below sea level at the Morgantown powerplant.