Approximate Regional Groundwater Divide on Long Island, New York, April-May 2016

Start Date

2016-04-15

End Date

2016-05-26

Publication Date

2018-06-06

Finkelstein, J.S., and Como, M.D., 2018, Geospatial dataset of water-table and potentiometric-surface altitudes in the upper glacial, Magothy, and Lloyd aquifers of Long Island, New York, April–May 2016: U.S. Geological Survey data release, https://doi.org/10.5066/F7G15Z9T.

Type: PDF Download

Each year during April and May, the USGS conducts a synoptic survey of water levels to define the spatial distribution of the water table and potentiometric surfaces within the three main water-bearing units (aquifers) underlying Long Island—the upper glacial, Magothy, and Lloyd aquifers and the hydraulically connected Jameco and North Shore aquifers. These data and the maps constructed from them are commonly used in studies of Long Island’s hydrology and are utilized by water managers and suppliers for aquifer management and planning purposes. Water-level measurements made in 424 monitoring wells (observation and supply wells) and 15 streamgage locations across Long Island during April–May 2016 were used to prepare the maps in this report. Measurements were made to the nearest hundredth of a foot using the wetted-tape method at groundwater wells and stage data at streamgaging stations were averaged for the months of April and May. Contours of water-table and potentiometric-surface altitudes were created using the groundwater measurements. The water-table contours were interpreted using water-level data collected from 13 streamgages, 2 lake gages, 275 observation wells, and 1 supply well screened in the upper glacial aquifer or the shallow Magothy aquifer. The potentiometric-surface contours of the Magothy aquifer were interpreted from measurements at 88 wells (61 observation wells and 27 supply wells) screened in the middle to deep Magothy aquifer and the contiguous and hydraulically connected Jameco aquifer. The potentiometric-surface contours of the Lloyd aquifer were interpreted from measurements at 60 wells (55 observation wells and 5 supply wells) screened in the Lloyd aquifer and the contiguous and hydraulically connected North Shore aquifer. Editing of the geospatial data was conducted in ArcGIS Desktop (Esri, 2015a) using geographic information system (GIS) tools. All water-level altitudes are referenced to the National Geodetic Vertical Datum of 1929 (NGVD 29).

ArcGIS Mapping Service

WMS Service

• USGS New York Water Science Center

Data source

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