Geology and ground-water resources of Camden County, New Jersey

The major fresh water aquifers in Camden County, N. J., are in the unconsolidated sediments of Cretaceous and Tertiary age. The major aquifers are the sand and gravel units in the Potomac Group and the Raritan and Magothy Formations, the Cohansey Sand, the Wenonah Formation-Mount Laurel Sand, and the Englishtown Formation. The average ground-water use for Camden County was 68 million gallons per day for 1966. All of the major artesian aquifers have had potentiometric head declines due to ground-water withdrawals. The largest water-level decline occurred in the aquifer system in the Potomac Group and the Raritan and Magothy Formations. At Haddon Heights the potentiometric head declined over 110 feet from 1900 to 1968. In the aquifer in the Wenonah Formation-Mount Laurel Sand the potentiometric head declined 43 feet in about 60 years. The quality of ground water is generally good. In the southeastern portion of the county chloride concentrations in excess of 250 mg/liter occur in the Potomac-Raritan-Magothy aquifer system. The high chloride water has remained in the aquifer system from the time of deposition or has re-entered the system from the ocean after the changes in sea level. The greatest potential of future ground-water development is from the Cohansey Sand which is under water table conditions. It also may have the greatest possibility of local ground-water contamination. (Woodard-USGS)