Long Island, which in the early 21st Century had a population of nearly 3 million, is dependent for its water supply on groundwater. The amount of water available is controversial with attention focusing on the deepest aquifer, the Lloyd Aquifer which lies just about bedrock beneath the island. It is separated from shallower aquifers, the Magothy Aquifer and the Upper Glacial Aquifer by a layer of clay. Separated from the mainland by Long Island Sound except at is southwestern end at New York City, Long Island has no significant rivers or lakes.
Each day 450 million gallons are pumped from 1,300 large capacity wells and thousands of small private wells, with consumption greatest in the summer. Long Island residents use an average of 150 gallons per person each day. The biggest supplier, Suffolk County Water Authority, serves 1.1 million people.
Suffolk County Water Authority has applied to drill into the Lloyd Aquifer in order to obtain clean water to blend with water from an existing well contaminated with nitrates. This is controversial as the Lloyd Aquifer is subject to a moratorium on drilling imposed in 1986 by Section 15-1528 of the New York State Environmental Conservation Law ("ECL") which provides for a moratorium on the granting of new permits to drill public water supply wells in the Lloyd Aquifer in areas that are not coastal communities unless an exemption is granted by the New York State Department of Environmental Conservation.
The well is opposed by the Sierra Club and the League of Women Voters and by other communities which draw water from the aquifer. Opponents contend that pumping is lowering the water table, spreading contaminants and resulting in saltwater intrusion. Contamination is common on Long Island from many sources in including cesspool and sewage effluent, fuel leaks, fertilizer, pesticide and garbage dumps. However, the surface aquifers are replenished by rain and the Suffolk County Water Authority regularly tests the quality of groundwater and filters or blends contaminated water. Sewer treatment is improving and toxic sites are being cleaned up. The Long Island Pine Barrens are preserved as open space. According to Lee E. Koppelman, director of the Center for Regional Policy Studies at Stony Brook University water quality on Long Island is high.
However in intensely urbanized southwestern Long Island the aquifers beneath Brooklyn and Queens are contaminated and depleted. Their water comes from the Catskills and the Hudson River for water. Many wells in Nassau and Suffolk Counties have been contaminated with pollution or saltwater.
Alternatives to use of groundwater seem prohibitively expensive while potential water conservation remains unimplemented and water remains low priced. The island was designated by the Environmental Protection Agency as an area depending on a "sole source aquifer, but allocation of the water is subject to many agencies and water suppliers." A state agency to manage the water has been proposed. The Long Island Groundwater Research Institute at The State University of New York at Stony Brook is devoted to study of the problems.
- "Nassau-Suffolk Aquifer System" EPA information page
- "As Aquifer Runs Dry, L.I. Water Debate Ensues" New York Times article by Bruce Lambert, December 2, 2006
- Application for exemption from moratorium as installation of public water supply well in the Lloyd Aquifer Suffolk County Water Authority; Middleville Road Well #3
- FAQ Suffolk County Water Authority
- Long Island Groundwater Research Institute