Michael D. Como Jason S. Finkelstein Jack Monti, Jr. Ronald Busciolano 20221117 unknown Vector Digital Data Set (Point) Scientific Investigations Map 3326 Reston, VA U.S. Geological Survey Data set appears on Sheet 1 from SIM 3326 Michael D. Como Michael L. Noll Jason S. Finkelstein Jack Monti, Jr. Ronald Busciolano 20150519 Publication (Other) Scientific Investigations Map 3326 Como, M.D., Noll, M.L., Finkelstein, J.S., Monti, Jack, Jr., and Busciolano, Ronald, 2015, Water-table and potentiometric-surface altitudes in the Upper Glacial, Magothy, and Lloyd aquifers of Long Island, New York, April–May 2013: U.S. Geological Survey Scientific Investigations Map 3326, 4 sheets, scale 1:125,000, 6-p. text http://pubs.usgs.gov/sim/3326/ Water level altitudes were measured at 334 observation wells and 1 supply well screened in the upper glacial and Magothy aquifers during April and May of 2013. This shapefile consists of the locations of those sites and includes water level altitude data stored in the attribute table. The shapefile was created and intended for use with geographic information system (GIS) software. The measurement locations and altitude values in this point shapefile are also presented in Sheet 1 of Scientific Investigations Map 3326. 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 502 monitoring wells (observation and supply wells) and 16 streamgage locations across Long Island during April–May 2013 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 by using the groundwater measurements. The water-table contours were interpreted using water-level data collected from 16 streamgages, 334 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 70 observation wells and 31 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 58 observation wells and 8 supply wells screened in the Lloyd aquifer and the contiguous and hydraulically connected North Shore aquifer. In SIM 3326, all water-level altitudes are referenced to the National Geodetic Vertical Datum of 1929 (NGVD 29). The upper glacial aquifer of Pleistocene age is the uppermost unit in Long Island’s groundwater system and contains the water table throughout the island, except in parts of central and eastern Nassau County and western Suffolk County where the entire upper glacial aquifer is unsaturated and the water table is in the shallow Magothy aquifer. The upper glacial aquifer was the principal source of water supply throughout Long Island, but contamination in many areas has resulted in the widespread curtailment of its use for public supply. The general configuration of the water table is an east-west mound that coincides with the topographic high (region of higher land surface altitude) and the glacial moraine along the center of the island with isolated areas of higher water levels in central Nassau County and in central Suffolk County. Local highs also are present in northwestern Nassau County and the central part of the southern peninsula of eastern Suffolk County. These areas of higher water levels are a result of the low hydraulic conductivity of the geologic units underlying these wells. The water-table altitude on Long Island during April–May 2013 ranged from zero feet (ft) along the shore to more than 121 ft above NGVD 29 in northwestern Nassau County. In Kings County, 20 measurements ranged from 1.19 to 16.55 ft; in Queens County, 34 measurements ranged from 0.74 to 46.39 ft; in Nassau County, 71 measurements ranged from 1.84 to 121.71 ft; and in Suffolk County, 210 measurements ranged from 1.29 to 78.67 ft above NGVD 29. 20130401 20130530 ground condition Complete None planned -74.021143 -71.863683 41.162202 40.559478 ISO 19115 Topic Category geoscientificInformation inlandWaters environment None USGS upper glacial Aquifer Hydrology Water level Groundwater Levels water table Magothy Aquifer USGS Metadata Identifier USGS:56f596dfe4b06639d52a3a18 None Kings County Long Island New York Queens County Nassau County Suffolk County None This data set was compiled at a scale of 1:125,000 ACCURACY STATEMENT: These digital data have gone through rigorous, multi-level, quality-control process. If errors are encountered in the data set it will be appreciated if the user would pass this information to the metadata contact. APPROPRIATE USE: Appropriate use of these data is determined initially by the scale from which the data base was developed. Use this data set with similarly-scaled data. Mixing scales could adversely impact the accuracy of any calculations derived from these data. When mixing scales in any analysis your final result is only as accurate as your smallest scale map used. U.S. Geological Survey, Northeast Region Michael D. Como Hydrologist mailing

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Coram NY 11727 631-736-0783 x120 631-736-4283 mcomo@usgs.gov 9-5:30 Prepared in cooperation with: Long Island Water Conference, Nassau County Department of Public Works, New York City Department of Environmental Protection, Port Washington Water District, Suffolk County Department of Health Services, Towns of North Hempstead and Shelter Island, Manhasset-Lakeville Water District Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.3.1.4959 Supply wells were turned off for a minimum of 24 hours before measurements were made to allow the water levels in the wells to recover to ambient (non-pumping) conditions. Full recovery time at some of these supply wells can exceed 24 hours; therefore, water levels measured at these wells are assumed to be less accurate than those measured at observation wells, which are not pumped. In addition to pumping stresses, elevated chloride concentrations (saline water) also lower the water levels measured in certain wells. This reduction in water level is the result of saline water being denser than freshwater. No formal logical accuracy tests were conducted. This point shapefile includes 335 point features, each representing a depth to water measurement in April-May 2013. These data are published on sheet 1 of the Scientific Investigations Map 3326. The error is assumed to be +/- 64 meters due to the scale at which the data were created. Calculated and interpreted from point data in reference to NGVD 1929 U.S. Geological Survey 20130829 Other Reston, VA U.S. Geological Survey hardcopy 20130402 20130528 publication date NWIS The source provided water level data in the upper glacial and Magothy aquifers at 335 groundwater monitoring wells RETRIEVAL- Measured water levels referenced to the National Geodetic Vertical Datum of 1929 were retrieved from the USGS National Water Information System. 20150519 Vector Entity point 335 NAD 1983 StatePlane New York Long Island FIPS 3104 Feet 40.66666666666666 41.03333333333333 -74.0 40.16666666666666 984250.0 0.0 coordinate pair 0.00000002687262634637478 0.00000002687262634637478 foot_us D North American 1983 GRS 1980 6378137.0 298.257222101 2013_Water_Table_Points Table containing attribute information associated with the data set. Producer defined FID Internal feature number. Esri Sequential unique whole numbers that are automatically generated. Shape Feature geometry. Esri Coordinates defining the features. Site_ID USGS site identifier Producer defined USGS site identifier Station_Na Station name Producer defined Station name consists of county identifier, well number, and well sequence number. For example, "K 3250. 2", where "K" indicates King's County, "3250" is the well number, and "2" is the sequence number. WL_Date Water level date Producer defined 4/2/2013 5/28/2013 Time WL_Time Water level time Producer defined 610 1800 Time WL_TimeDat Water level time datum Producer defined EST Eastern standard time Producer defined Y_Latitude Latitude of well referencing the North American Datum of 1983 Producer defined 40.5789941 41.14954278 Decimal degrees X_Longitud Longitude of well referencing the North American Datum of 1983 Producer defined -74.02097317 -71.866 Decimal degrees HYPERLINK Hyperlink to source data Producer defined Hyperlink to water level data in the USGS National Water Inventory System. SUPPLY_WEL Supply Well Producer defined {Null Value / Empty Field Entry} Unknown Producer defined Y Indicates that the well is a supply well. Producer defined AQUIFER Aquifer Producer defined Magothy Well is screened in the Magothy aquifer. Producer defined Upper Glacial Well is screened in the upper glacial aquifer. Producer defined WL_Ref_to_ Water level referenced to the National Geodetic Vertical Datum of 1929 Producer defined 0.74 121.71 Water level values are in feet above or below NGVD 1929 with measurements ranging from 0.74 to 121.71 feet above NGVD 1929. Como, M.D., Finkelstein, J.S., Monti, Jack, Jr., and Busciolano, Ronald, 2016, Geospatial dataset of water-table and potentiometric-surface altitudes in the upper glacial, Magothy, and Lloyd Aquifers of Long Island, New York, April-May 2013: U.S. Geological Survey data release, http://dx.doi.org/10.5066/F7RV0KSD. U.S. Geological Survey, Northeast Region Michael D. Como Hydrologist mailing

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Coram NY 11727 631-736-0783 x120 631-736-4283 mcomo@usgs.gov Although these data have been processed successfully on a computer system at the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Vector Digital Data Set (Point) https://doi.org/10.5066/F7RV0KSD None. No fees are applicable for obtaining the data set. 20260430 U.S. Geological Survey, Northeast Region Jason S. Finkelstein Hydrologist mailing

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Coram NY 11727 631-736-0783 x135 631-736-4283 jfinkels@usgs.gov 9-5:30 FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998 local time