Potentiometric surface of the Aquia Aquifer in southern Maryland during September 1988

A map showing the potentiometric surface of the Aquia aquifer in the Paleocene Aquia Formation in southern Maryland during the fall of 1988 was constructed on the basis of water level measurements made at 84 observation wells. The potentiometric surface was above sea level near the northwestern boundary and outcrop area of the aquifer in topographically high areas of Anne Arundel and Prince Georges Counties; it was below sea level in the remainder of the study area. The hydraulic gradient generally was to the southeast toward an extensive cone of depression centered around well fields near Lexington Park and Solomons Island. Water levels were more than 60 ft below sea level in a 50 sq-mi area near the center of the cone and were more than 100 ft below sea level at two of the wells near the center of the cone. (USGS)