The difference between the potentiometric surfaces of the lower Patapsco aquifer, September 1990 and September 1999 in southern Maryland

This report presents a map showing the change in the potentiometric surface of the Lower Patapsco aquifer in the Lower Patapsco Formation of Cretaceous age in Southern Maryland for September 1990 and September 1999. The map, based on water?level measurements in 52 wells, shows that the change of the potentiometric surface during the 9- year period ranged from a rise of 13 feet at Indian Head and 6 feet near the outcrop area in Glen Burnie, to declines of 34 feet at Arnold, 30 feet at Waldorf, and 24 feet at Morgantown.