Hydrogeology of the southwestern part of the town of Hempstead, Nassau County, New York

Water-Resources Investigations Report 85-4288



The groundwater resources of the southwestern part of the Town of Hempstead in Nassau County, NY were investigated in 1984. The area studied encompasses 85 sq mi, or 68% of the town 's 125-sq mi area. The groundwater reservoir underlying the area consists of unconsolidated gravel, sand, silt, and clay of Holocene, Pleistocene, and Late Cretaceous age that have been divided into eight geologic units. The maximum total thickness of the unconsolidated deposits is about 1,500 ft. Precipitation is the sole source of groundwater recharge in the area. The average annual precipitation, as recorded at Valley Stream during 1927-83, was 42.62 in. The water table altitude in the 1980 's has recovered and equalled or exceeded that before the regional drought of 1962-66. The potentiometric surfaces in the Magothy and Lloyd aquifers are still somewhat below those before the drought but are recovering throughout most of the area. The report presents 10 maps showing the surface altitude of the geologic units as well as the potentiometric altitudes of the three major aquifers. Also included are six geologic sections, four hydrographs, and several graphs presenting the data that was collected. (USGS)
Publication type Report
Publication Subtype USGS Numbered Series
Title Hydrogeology of the southwestern part of the town of Hempstead, Nassau County, New York
Series title Water-Resources Investigations Report
Series number 85-4288
DOI 10.3133/wri854288
Edition Revision
Year Published 1989
Language ENGLISH
Publisher U.S. Geological Survey ; Copies may be purchased from Books and Open-File Reports Section,
Description iv, 16 p. :ill., maps ;28 cm.
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