Reconnaissance of the ground-water resources of Kings and Queens counties, New York

Western Long Island 's ground-water resources are being considered for redevelopment as a supplemental source of public water supply. The ground-water reservoir in Kings and Queens Counties had supplied an average of more than 120 million gallons per day for industrial and public water supply from 1904 to 1947. However, deterioration of groundwater quality from induced encroachment of salty ground-water caused the total cessation of pumping for public supply in Kings County in 1947 and in western Queens County in 1974. This investigation was designed to make a preliminary evaluation of the present groundwater quality and to review hydrologic information pertinent to the formulation of an appropriate development plan. Detailed hydrogeologic mapping was done to define the geometry of the ground-water system. The history of ground-water development and the consequent responses of ground-water levels and quantity were summarized. A well network was established to monitor ground-water levels and ground-water quality in Kings and Queens Counties. The distribution of chloride and nitrate in ground-water was used to identify contamination from salt-water intrusion and surface sources. A limited source of potable ground-water is available in the Magothy-Jameco and Lloyd aquifers; however, an accurate estimate of the quantity of water available or a draft rate suitable for maintaining a useable ground-water quality is undetermined. (USGS)