From 1965-79, a chemical reclamation facility, now known as the Swope Oil Superfund site, sold and processed a variety of chemical compounds. Operation of the facility resulted in contamination of ground water beneath the 1.9-acre site. During 1984, the maximum concentrations of chromium and lead in ground water were 64 and 90 jug/L (micrograms per liter), respectively; the maximum concentration of total purgeable organic compounds (POCs) was 108 jug/L; and the maximum concentration of total base/neutraland acid-extractable organic compounds was 116 jug/L. Although the off-site migration of these compounds has not been studied, a public-supply well 300 feet from the site is contaminated, and a public-supply well 1,400 feet from the site may be threatened. The study area is adjacent to the tidally influenced Delaware River and is situated in the New Jersey part of the Atlantic Coastal Plain physiographic province. This province consists of a wedge of unconsolidated sediment which thickens and dips toward the Atlantic Ocean. The study area is underlain by alluvial deposits, the Cretaceous Merchantville-Woodbury confining unit, and the Potomac-Raritan-Magothy aquifer system. These deposits, which are composed of gravel, sand, silt, and clay, crop out in the study area and are underlain by bedrock. These hydrogeologic units comprise the water-table aquifer, the confining units, and the confined aquifer found throughout the study area. The Potomac-Raritan-Magothy aquifer system is incised by the Delaware River and is hydraulically connected to it. Regional estimates of hydraulic conductivities of aquifers and confining units in Cretaceous rocks are 130 to 350 ft/d (feet per day), and approximately 2.0 x 10 2 ft/d, respectively. The average yield of wells 6 inches or larger in the confined aquifer is approximately 1190 gallons per minute; specific capacity ranges from 17 to 80 gallons per minute per foot of drawdown. The surface of the water table beneath the Swope Oil Superfund site is approximately 17 feet below sea level. Groundwater levels throughout the study area are believed to be below the stage of the Delaware River, causing induced recharge to the Potomac-Raritan-Magothy aquifer system from the river. Precipitation is the principal source of recharge to the water-table aquifer. Induced recharge into aquifers of the Potomac-Raritan-Magothy aquifer system from the Delaware River and downward leakage of water through confining units toward pumping centers in Camden County are the principal sources of recharge to the confined aquifer. Five public-supply well fields are located in the study area, primarily adjacent to the Delaware River. During 1983 public-supply wells pumped approximately 25 million gallons per day of water, which accounts for approximately 30 percent of all groundwater withdrawals by public-supply wells in Camden County. Four waste-disposal sites with observation-well networks are also located in the study area. The water-table and confined aquifers are contaminated in several locations in the s...

Plate 1. Camden West and Camden East quadrangles: A. Location of wells, streamflow-measurement sites, and seismic survey sites B. Surficial geology C. Bedrock-surface altitude D. Potentiometri c surface of unconf ined aquifer and hydrographs of selected wells E. Potential well yields F. Land use 2. Williamstown and Westdale quadrangles: A. Location of wells, streamf1ow-measurement sites, and seismic survey sites B. Surficial geology C. Bedrock-surface altitude D. Potentiomet ric surface of unconf ined aquifer and hydrographs of selected wells E. Potential well yields F. La nd use 3. Richland and Orwell quadrangles: A. Location of wells, streamflow-measurement sites, and seismic survey sites B. Surficial geology C. Bedrock-surf ace altitude D. Potentiometrie surface of unconfined aquifer and hydrographs of selected wells E. Potential well yields F. Land use 4. Sandy Creek, Adams, and Rodman quadrangles: A. Location of wells, streamflow-measurement sites, and seismic survey sites B. Surficial geology C. Bedrock-surface altitude D. Potentiometric surface of unconfined aquifer and hydrographs of selected wells E. Potential well yields F. Land use vi

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