The Difference Between the Potentiometric Surfaces of the Magothy Aquifer in Southern Maryland, September 1975 and September 2009

This report presents a map showing the change in the potentiometric surface of the Magothy aquifer in the Magothy Formation of Late Cretaceous age in Southern Maryland between September 1975 and September 2009. The map, based on water level differences obtained from 48 wells, shows that during the 34-year period, the potentiometric surface had little change at the outcrop area, which is in the northernmost part of the study area, but declined 75 feet at Waldorf. Waldorf is located near the southwesternmost part of the study area, and approaches the downdip boundary of the aquifer. The map also shows well yield in gallons per day for 2008 at wells or well fields.