Atlantic Coastal Plain aquifer system

Atlantic Coastal Plain aquifer system
Name	Atlantic Coastal Plain aquifer system
Type	Aquifer system
Location	Eastern United States
Countries	United States
States	Maine, New Hampshire, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, Pennsylvania, Delaware, Maryland, Virginia, North Carolina, South Carolina, Georgia
Lithology	Sedimentary sands, gravels, silts, clays

Atlantic Coastal Plain aquifer system is a widespread groundwater province underlying the Atlantic Ocean seaboard from New York through Georgia. It supplies municipal, agricultural, industrial, and military installations with freshwater and interacts with coastal ecosystems such as the Chesapeake Bay and Delaware Bay. Studies by agencies including the United States Geological Survey and the Environmental Protection Agency have characterized its stratigraphy, resource potential, and vulnerabilities.

Overview

The aquifer system occupies the Atlantic Coastal Plain physiographic province and underlies portions of states from Long Island and New Jersey to Georgia. It comprises multiple unconsolidated and semi-consolidated Tertiary and Quaternary sedimentary units deposited during events tied to the Pliocene, Pleistocene, and Holocene epochs. Major population centers and installations such as New York City, Philadelphia, Baltimore, Norfolk, and Savannah rely on wells finished in these aquifers, while ports such as Port Newark-Elizabeth Marine Terminal and Port of Virginia interact with groundwater through land use and seawater intrusion dynamics.

Geology and Hydrostratigraphy

Bedrock geology beneath the aquifer system includes Paleozoic and Mesozoic strata of the Appalachian Mountains region and the Piedmont, overlain by Coastal Plain sedimentary sequences studied in cores from projects such as the Deep Sea Drilling Project and the International Ocean Discovery Program. Hydrostratigraphic units include regional aquifers and confining layers correlated to formations like the Potomac Group equivalents and Miocene and Pliocene shoreface deposits recognized in atlases produced by the United States Geological Survey. Mapping efforts integrate borehole logs from institutions including the National Oceanic and Atmospheric Administration and state geological surveys.

Aquifers and Confining Units

The system contains multiple named aquifers and confining units, including surficial unconfined aquifers, intermediate confined aquifers, and deep artesian aquifers used historically and presently by utilities such as New Jersey American Water Company and Philadelphia Water Department. Notable aquifers include sediments correlated with the Potomac Formation, the Tallahatta Formation equivalents, and younger Pleistocene terrace deposits. Confining units of low permeability—clayey sequences analogous to the Raritan Formation and Clayton Formation—separate water-bearing layers and influence pumping-induced drawdown and inter-aquifer leakage.

Groundwater Flow and Recharge

Regional groundwater flow generally follows topographic gradients toward the Atlantic Ocean and major estuaries including the Chesapeake Bay and Delaware Bay, with local flow influenced by features such as the Hudson River estuary and barrier island systems like Cape Cod. Recharge occurs via precipitation infiltrating sandy surficial deposits in landscapes managed by agencies such as the National Park Service at sites like Fire Island National Seashore and Cape Hatteras National Seashore, and via induced recharge from rivers such as the James River and Savannah River. Coastal hydraulic gradients are modulated by sea-level changes associated with Holocene sea level rise and events recorded in Atlantic hurricane season impacts.

Water Use and Management

Municipal utilities, industrial complexes, irrigation districts, and military bases including Naval Station Norfolk and Fort Bragg extract freshwater from the aquifer system. Management frameworks involve federal and state entities such as the United States Geological Survey, the Environmental Protection Agency, the Florida Department of Environmental Protection, and the New Jersey Department of Environmental Protection, alongside regional commissions like the Chesapeake Bay Program. Policies address allocation, permitting, drought contingency, and interbasin transfers near urban centers like Charlotte, North Carolina and Miami metro areas.

Contamination and Vulnerabilities

The aquifer system is vulnerable to contaminants including nutrients from Delaware Valley agriculture, chlorinated solvents near industrial corridors such as the Route 1 (U.S. Route 1) corridor, and petroleum products around ports like the Port of New York and New Jersey. Coastal sections face seawater intrusion recognized in studies for Long Island, Cape May County, New Jersey, and the Outer Banks, exacerbated by groundwater withdrawals and relative sea-level rise. Legacy contaminants associated with military activities at installations like Camp Lejeune and industrial discharges cataloged under Superfund sites create persistent plumes requiring remediation.

Conservation and Restoration

Conservation measures include managed aquifer recharge projects, wellhead protection delineated under state programs such as New Jersey’s Source Water Protection, and restoration of coastal wetlands in initiatives by the National Oceanic and Atmospheric Administration and the US Army Corps of Engineers to buffer saltwater intrusion and enhance recharge. Protected areas like Assateague Island National Seashore and watershed partnerships such as the Chesapeake Bay Foundation integrate groundwater considerations into regional conservation and land-use planning.

Research and Monitoring Studies

Long-term monitoring networks operated by the United States Geological Survey, state geological surveys, and academic centers including Woods Hole Oceanographic Institution, University of North Carolina at Chapel Hill, Rutgers University, University of Maryland, College Park, and Georgia Institute of Technology track water levels, salinity, and contaminant trends. Research topics span paleohydrology, managed aquifer recharge, contaminant hydrogeology, and coupled groundwater–surface water modeling using tools developed by institutions such as the National Center for Atmospheric Research and the Environmental Protection Agency. Collaborative projects with programs like the National Science Foundation advance understanding of resilience to climate-driven sea-level rise and urbanization impacts.

Category:Aquifers Category:Atlantic Coastal Plain