U.S. Department of the Interior

U.S. Geological Survey

Pamphlet to accompany 

Scientific Investigations Map 3398

Prepared in cooperation with the

Manhasset-Lakeville Water District, Nassau County Department of Public Works,

New York State Department of Environmental Conservation, Port Washington Water District,

Sands Point Water Department, Suffolk County Department of Health Services,

Suffolk County Water Authority, Town of North Hempstead, Town of Shelter Island, and

Water Authority of Great Neck North

Water-Table and Potentiometric-Surface Altitudes in 

the Upper Glacial, Magothy, and Lloyd Aquifers 

of Long Island, New York, April–May 2016
Cover photo: Composite of U.S. Geological Survey Landsat 8 imagery from October 27 and 

November 21, 2017, showing Long Island, New York.
Water-Table and Potentiometric-Surface 

Altitudes in the Upper Glacial, Magothy, 

and Lloyd Aquifers of Long Island, New 

York, April–May 2016

By Michael D. Como, Jason S. Finkelstein, Simonette L. Rivera, Jack Monti, Jr., 

and Ronald Busciolano

Prepared in cooperation with the

Manhasset-Lakeville Water District

Nassau County Department of Public Works

New York State Department of Environmental Conservation

Port Washington Water District

Sands Point Water Department

Suffolk County Department of Health Services

Suffolk County Water Authority

Town of North Hempstead

Town of Shelter Island

Water Authority of Great Neck North

Pamphlet to accompany

Scientific Investigations Map 3398 

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

RYAN K. ZINKE, Secretary

U.S. Geological Survey

James F. Reilly II, Director

U.S. Geological Survey, Reston, Virginia: 2018

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Suggested citation:

Como, M.D., Finkelstein, J.S., Rivera, S.L., Monti, Jack, Jr., and Busciolano, Ronald, 2018, 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 Scientific Investigations Map 3398, 4 sheets, scale 1:125,000, 5-p. pamphlet, 

https://doi.org/10.3133/sim3398.

ISSN 2329-132X (online)
iii

Contents

Sheet 1—Upper Glacial and Shallow Magothy Aquifers (Water Table) ..............................................1

Introduction............................................................................................................................................1

Upper Glacial and Shallow Magothy Aquifers (Water Table) .......................................................2

References Cited...................................................................................................................................2

Sheet 2—Potentiometric Surface in the Magothy and Jameco Aquifers ...........................................2

References Cited...................................................................................................................................3

Sheet 3—Potentiometric Surface in the Lloyd and North Shore Aquifers ..........................................3

References Cited...................................................................................................................................4

Sheet 4—Depth to Water Table ..................................................................................................................4

Groundwater-Level Data Retrieval ....................................................................................................5

References Cited...................................................................................................................................5
Sheet 1—Upper Glacial and Shallow 

Magothy Aquifers (Water Table)

Introduction

The U.S. Geological Survey (USGS), in cooperation 

with State and local agencies, systematically collects groundwater data at varying measurement frequencies to monitor 

the hydrologic conditions on Long Island, New York. Each 

year during April and May, the USGS completes 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 underlying Long Island—the upper 

glacial, Magothy, and Lloyd aquifers (Smolensky and others, 

1990)—and the hydraulically connected Jameco (Soren, 1971) 

and North Shore aquifers (Stumm, 2001). These data and the 

maps constructed from them are commonly used in studies of 

the hydrology of Long Island and are used by water managers 

and suppliers for aquifer management and planning purposes.

Water-level measurements made in 424 monitoring wells 

(observation and supply wells), 13 streamgages, and 2 lake 

gages across Long Island during April–May 2016 were used to 

prepare the maps in this report (Finkelstein and Como, 2018). 

Groundwater measurements were made by the wetted-tape or 

electric-tape method to the nearest hundredth of a foot. 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 275 observation wells and 1 supply well screened in 

the upper glacial aquifer and the shallow Magothy aquifer 

and 13 streamgages and 2 lake gages. The potentiometricsurface 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. Many of the supply wells are in continuous operation and, 

therefore, 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 (nonpumping) 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 (Busciolano, 2002). In addition to pumping 

stresses, density differences (saline water) also lower the water 

levels measured in certain wells (Lusczynski, 1961). Recent 

water-quality data are lacking in these wells; therefore, a conversion to freshwater head could not be performed accurately 

and was not attempted. In this report, all water-level altitudes 

are referenced to the National Geodetic Vertical Datum of 

1929 (NGVD 29).

The land surface altitude, or topography, was obtained 

from the National Oceanic and Atmospheric Administration 

(2016). The data were collected using light detection and 

ranging (lidar) and were used to produce a three-dimensional 

digital elevation model. The lidar data have a horizontal 

accuracy of 1.38 feet (ft) and a vertical accuracy of 0.40 ft at a 

95-percent confidence level for the “open terrain” land-cover 

category. The digital elevation model was developed jointly by 

the National Oceanic and Atmospheric Administration and the 

U.S. Geological Survey as part of the Disaster Relief Appropriations Act of 2013 (Pub.L. 113–2, H.R. 152, 127 Stat. 4). 

Land surface altitude is referenced to the North American Vertical Datum of 1988 (NAVD 88). On Long Island, NAVD 88 is 

approximately 1 foot higher than NGVD 29. 

Hydrographs are included on these maps for selected 

wells that have continuous digital recording equipment, and 

each hydrograph includes the water level measured during 

the synoptic survey. These hydrographs are representative of 

the 2016 water year and show the changes throughout that 

period; a water year is the 12-month period from October 1 to 

September 30 and is designated by the year in which it ends.

Water-Table and Potentiometric-Surface Altitudes in the 

Upper Glacial, Magothy, and Lloyd Aquifers of Long Island, 

New York, April–May 2016

By Michael D. Como, Jason S. Finkelstein, Simonette L. Rivera, Jack Monti, Jr., and Ronald Busciolano
2 Water-Table and Potentiometric-Surface Altitudes in Aquifers, Long Island, New York, April–May, 2016

Upper Glacial and Shallow Magothy Aquifers 

(Water Table)

The upper glacial aquifer of Pleistocene age is the 

uppermost unit in the groundwater system of Long Island 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 for several decades, but contamination 

in many areas resulted in the widespread curtailment of its use 

for public supply. The general configuration of the water table 

forms 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 (Stumm and others, 2002) and the central 

part of the southern peninsula (south fork) of eastern Suffolk 

County (Schubert and others, 2004). 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 2016 ranged from 0 ft above NGVD 29 along the 

shore to more than 120 ft above NGVD 29 in northwestern 

Nassau County. No measurements were collected in Kings 

County, 1 measurement of 16.91 ft was collected in Queens 

County, 76 measurements ranging from 1.64 to 120.93 ft were 

collected in Nassau County, and 199 measurements ranging 

from 1.51 to 75.36 ft were collected in Suffolk County 

(all measurements were referenced to NGVD 29).

A geographic information system was used to create a 

continuous surface of the water table using an iterative finite 

difference interpolation technique with measurements from 

275 observation wells, 1 supply well, 13 streamgages, 2 lake 

level gages, interpreted 10-ft contour intervals, and the coastline (Esri, 2015). The approximate location of the regional 

groundwater divide for the water table was included on the 

map as a black dashed line which was drawn along the ridge 

of maximum water-table altitude.

References Cited

Busciolano, Ronald, 2002, Water-table and potentiometricsurface altitudes of the upper glacial, Magothy, and Lloyd 

aquifers on Long Island, New York, in March–April 2000, 

with a summary of hydrogeologic conditions: U.S. Geological Survey Water-Resources Investigations Report 01–4165, 

17 p., 6 pls. [Also available at https://pubs.usgs.gov/

wri/2001/4165/wri20014165.pdf.]

Esri, 2015, ArcMap 10.4.1: Redlands, Calif., Esri, software. 

[Also available at http://desktop.arcgis.com/en/arcmap/10.4/

get-started/main/get-started-with-arcmap.htm.]

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.

Lusczynski, N.J., 1961, Head and flow of ground water 

of variable density: Journal of Geophysical Research, 

v. 66, no. 12, p. 4247–4256. [Also available at 

https://doi.org/10.1029/JZ066i012p04247.]

National Oceanic and Atmospheric Administration, 2016, 

NCEI Hurricane Sandy digital elevation models: National 

Centers for Environmental Information, digital data, 

accessed January 8, 2016, at https://www.ngdc.noaa.gov/

mgg/inundation/sandy/sandy_geoc.html.

Schubert, C.E., Bova, R.G., and Misut, P.E., 2004, Hydrogeologic framework of the North Fork and surrounding areas, 

Long Island, New York: U.S. Geological Survey WaterResources Investigations Report 2002–4284, 23 p., 4 pls., 

scale 1:120,000. [Also available at https://pubs.er.usgs.gov/

publication/wri024284.]

Smolensky, D.A., Buxton, H.T., and Shernoff, P.K., 1990, 

Hydrologic framework of Long Island, New York: 

U.S. Geological Survey Hydrologic Investigations Atlas 

HA–709, 3 sheets, scale 1:250,000. [Also available at 

https://pubs.er.usgs.gov/publication/ha709.]

Soren, Julian, 1971, Results of subsurface exploration in the 

mid-island area of western Suffolk County, Long Island, 

New York: Oakdale, N.Y., Suffolk County Water Authority, 

Long Island Resources Bulletin 1, 60 p.

Stumm, Frederick, 2001, Hydrogeology and extent of saltwater intrusion of the Great Neck peninsula, Great Neck, Long 

Island, New York: U.S. Geological Survey Water-Resources 

Investigations Report 99–4280, 41 p. [Also available at 

https://pubs.er.usgs.gov/publication/wri994280.]

Stumm, Frederick, Lange, A.D., and Candela, J.L., 2002, 

Hydrogeology and extent of saltwater intrusion on Manhasset Neck, Nassau County, New York: U.S. Geological 

Survey Water-Resources Investigations Report 00–4193, 

42 p. [Also available at https://pubs.er.usgs.gov/publication/

wri004193.]

Sheet 2—Potentiometric Surface in the 

Magothy and Jameco Aquifers

The Magothy aquifer of upper Cretaceous age is the 

most extensive unit in the groundwater system of Long Island. 

This aquifer underlies most of Long Island and the offshore 

waters, except in parts of western and northern Kings and 

Queens Counties, northern Nassau County, and northwestern 
Sheet 3—Potentiometric Surface in the Lloyd and North Shore Aquifers 3

and northeastern Suffolk County, where it has been removed 

by erosion and glacial scour. The altitude of its upper surface 

ranges from more than 200 feet (ft) above the National 

Geodetic Vertical Datum of 1929 (NGVD 29) in parts of 

north-central Nassau County and west-central Suffolk County 

to more than 600 ft below NGVD 29 in north-central Suffolk 

County (Smolensky and others, 1990). Aquifer thickness 

ranges from 0 ft in northern and western Kings and Queens 

Counties, northern Nassau County, and parts of northern 

Suffolk County to more than 1,000 ft in south-central 

Suffolk County (Soren and Simmons, 1987). The Magothy 

aquifer is the principal source of water supply in Nassau 

and Suffolk Counties.

This map depicts water levels during April–May 2016 in 

wells screened in the Magothy aquifer and the hydraulically 

connected Jameco aquifer. Most water-level measurements 

used to prepare this map (Finkelstein and Como, 2018) were 

made in wells screened near the middle of the aquifer and 

were supplemented by some measurements from the basal 

zone. Only a few water-level measurements made in the upper 

part of the aquifer were used. Because vertical hydraulic gradients in the Magothy aquifer can be large, measured potentiometric heads at a given location can vary depending on the 

depth of the well screen.

The general configuration of the potentiometric surface 

in the Magothy aquifer is similar to that of the water table, 

rising gradually from the western part of Long Island to form 

an east-west-trending mound in Nassau and western Suffolk 

Counties. The surface of the mound then gradually declines 

toward the eastern end of Long Island. In areas where deep 

channels have been eroded into the Magothy aquifer and filled 

with glacial deposits, the potentiometric-surface contours were 

drawn from water levels measured in wells screened in these 

upper glacial aquifer deposits, which are laterally contiguous and hydraulically connected to the Magothy aquifer. The 

inferred northern limit of the Magothy aquifer, the inferred 

extent of the Jameco aquifer, and the aquifer in which each 

well is screened are indicated on this map (Smolensky and 

others, 1990). Public-supply pumping and elevated chloride levels have lowered the potentiometric surface below 

NGVD 29 in southern Nassau County (Lusczynski and 

Swarzenski, 1966).

The altitude of the potentiometric surface in the Magothy 

aquifer on Long Island during April–May 2016 ranged from 

about 2 ft below NGVD 29 in extreme southwestern Nassau 

County to more than 76 ft above NGVD 29 in northeastern 

Nassau County. No measurements were collected in Kings 

and Queens Counties, 27 measurements ranging from −2.16 to 

76.34 ft were collected in Nassau County, and 61 measurements ranging from 3.31 to 72.87 ft were collected in Suffolk 

County (all measurements were referenced to NGVD 29).

References Cited

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.

Lusczynski, N.J., and Swarzenski, W.V., 1966, Salt-water 

encroachment in southern Nassau and southeastern Queens 

Counties, Long Island, New York: U.S. Geological Survey 

Water-Supply Paper 1613–F, 76 p. [Also available at 

https://pubs.er.usgs.gov/publication/wsp1613F]

Smolensky, D.A., Buxton, H.T., and Shernoff, P.K., 1990, 

Hydrologic framework of Long Island, New York: 

U.S. Geological Survey Hydrologic Investigations Atlas 

HA–709, 3 sheets, scale 1:250,000. [Also available at 

https://pubs.er.usgs.gov/publication/ha709.]

Soren, Julian, and Simmons, D.L., 1987, Thickness and hydrogeology of aquifers and confining units below the upper 

glacial aquifer on Long Island, New York: U.S. Geological 

Survey Water-Resources Investigations Report 86–4175, 

3 sheets, scale 1:125,000. [Also available at 

https://pubs.er.usgs.gov/publication/wri864175.]

Sheet 3—Potentiometric Surface in the 

Lloyd and North Shore Aquifers

The Lloyd aquifer of upper Cretaceous age is the basal 

unit of the groundwater system of Long Island. This aquifer 

continuously underlies most of Long Island and the offshore 

waters, except in parts of northern and western Kings, Queens, 

and Nassau Counties and extreme northeastern Suffolk County 

where it has been removed by erosion. The upper surface of 

the aquifer ranges in altitude from less than 100 feet (ft) below 

the National Geodetic Vertical Datum of 1929 (NGVD 29) 

in extreme northern parts of Queens County to more than 

1,500 ft below NGVD 29 in south-central Suffolk County 

(Smolensky and others, 1990). Aquifer thickness ranges 

from 0 ft in northern and western Kings, Queens, and Nassau 

Counties and extreme northeastern Suffolk County to more 

than 500 ft in extreme southeastern Nassau and southwestern 

Suffolk Counties (Soren and Simmons, 1987). 

This map depicts water levels during April–May 2016 in 

60 wells screened in the Lloyd and North Shore aquifers (Finkelstein and Como, 2018). Wells screened in the Pleistocene 

deposits of the North Shore aquifer in northern Nassau County 
4 Water-Table and Potentiometric-Surface Altitudes in Aquifers, Long Island, New York, April–May, 2016

are included because the North Shore aquifer is hydraulically 

connected to the Lloyd aquifer in these areas (Stumm, 2001; 

Stumm and others, 2002, 2004). The inferred northern extent 

of the Lloyd aquifer, the inferred extent of the North Shore 

aquifer, and the aquifer in which each well is screened are 

indicated on this map.

The general configuration of the potentiometric-surface 

altitude in the Lloyd aquifer is similar to those in the overlying 

water table and Magothy aquifers. The potentiometric surface 

gradually rises from the western part of Long Island to form 

an east-west-trending mound in eastern Nassau County that 

continues east into central Suffolk County. The mound then 

gradually declines toward the eastern end of Long Island. 

Public-supply and golf-course pumping has lowered the 

potentiometric surface in the Lloyd aquifer below NGVD 29 

in northwestern Nassau County (Stumm and others, 2002).

The potentiometric-surface altitude in the Lloyd aquifer 

on Long Island during April–May 2016 ranged from about 

9 ft below NGVD 29 in northwestern Nassau County to more 

than 58 ft above NGVD 29 in northeastern Nassau County. No 

measurements were collected in Kings County, 1 measurement 

of 7.51 ft was collected in Queens County, 52 measurements 

ranging from −8.81 ft (North Shore aquifer) to 58.50 ft were 

collected in Nassau County, and 7 measurements ranging from 

14.10 to 35.60 ft were collected in Suffolk County (all measurements were referenced to NGVD 29).

References Cited

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.

Smolensky, D.A., Buxton, H.T., and Shernoff, P.K., 1990, 

Hydrologic framework of Long Island, New York: 

U.S. Geological Survey Hydrologic Investigations Atlas 

HA–709, 3 sheets, scale 1:250,000. [Also available at 

https://pubs.er.usgs.gov/publication/ha709.]

Soren, Julian, and Simmons, D.L., 1987, Thickness and hydrogeology of aquifers and confining units below the upper 

glacial aquifer on Long Island, New York: U.S. Geological 

Survey Water-Resources Investigations Report 86–4175, 3 

sheets, scale 1:125,000. [Also available at 

https://pubs.er.usgs.gov/publication/wri864175.]

Stumm, Frederick, 2001, Hydrogeology and extent of saltwater intrusion of the Great Neck peninsula, Great Neck, Long 

Island, New York: U.S. Geological Survey Water-Resources 

Investigations Report 99–4280, 41 p. [Also available at 

https://pubs.er.usgs.gov/publication/wri994280.]

Stumm, Frederick, Lange, A.D., and Candela, J.L., 2002, 

Hydrogeology and extent of saltwater intrusion on Manhasset Neck, Nassau County, New York: U.S. Geological 

Survey Water-Resources Investigations Report 00–4193, 

42 p. [Also available at https://pubs.er.usgs.gov/publication/

wri004193.]

Stumm, Frederick, Lange, A.D., and Candela, J.L., 2004, 

Hydrogeology and extent of saltwater intrusion in the northern part of the town of Oyster Bay, Nassau County, New 

York: U.S. Geological Survey Water-Resources Investigations Report 03–4288, 55 p. [Also available at 

https://pubs.er.usgs.gov/publication/wri034288.]

Sheet 4—Depth to Water Table

This map depicts the depth to the water table beneath 

Long Island during April–May 2016. Areas in which the depth 

to water table is shallow are shown in red and indicate areas 

where potential substructure flooding is more likely.

A geographic information system was used to create a 

continuous surface of the water table using an iterative finite 

difference interpolation technique with measurements from 

275 observation wells, 1 supply well, 13 streamgages, 2 lake 

level gages, interpreted 10-foot (ft) contour intervals, and the 

coastline (Esri, 2015; Finkelstein and Como, 2018). 

The land surface altitude, or topography, was obtained 

from the National Oceanic and Atmospheric Administration 

(2016). The data were collected using light detection and 

ranging (lidar) and were used to produce a high accuracy 

three-dimensional digital elevation model. The digital elevation model was developed jointly by the National Oceanic 

and Atmospheric Administration and the U.S. Geological 

Survey as part of the Disaster Relief Appropriations Act of 

2013 (Pub.L. 113–2, H.R. 152, 127 Stat. 4). The datum for 

land surface altitude is the North American Vertical Datum of 

1988 (NAVD 88). On Long Island, NAVD 88 is approximately 

1 foot higher than the National Geodetic Vertical Datum of 

1929 (NGVD 29). The continuous surface of the water table 

was adjusted for the vertical datum differences, NGVD 29 to 

NAVD 88, using a raster that reflects local variations in the 

datum shift across Long Island. This interpolated surface was 

then subtracted from the topography at the same location. The 

results are shown as a continuous depth to water table map. 

Field measurements of depth to water (accurate to a hundredth 

of a foot) are also plotted on the map.

The general configuration of the depth to the water 

table reflects the topography data; however, because the map 

scales of the topography (1:24,000) and water-table altitude 

(1:125,000) differ, the horizontal accuracy of the depth to 

water table is 1:125,000 with a vertical error of plus or minus 
Sheet 4—Depth to Water Table 5

5 ft. Areas in which no water-level data were available for 

comparison are shown in gray; however, in areas along the 

south shore of Long Island, including marshes and the barrier 

island, the water-table altitude was assumed to be NGVD 29.

Groundwater-Level Data Retrieval

Groundwater-level data used to create this map product 

were obtained from the U.S. Geological Survey National 

Water Information System (NWIS) database (U.S. Geological Survey, 2017). The NWIS database consists of more than 

875,000 records of wells, springs, test holes, tunnels, drains, 

and excavations in the United States. Available site information includes well-location and completion information, such 

as latitude, longitude, well depth, and aquifer. Water-level 

data from the NWIS database can be queried and used to 

construct historical time-series hydrographs for wells. As an 

example, for Suffolk County mapped well “S16783,” go to 

the NWIS database (https://doi.org/10.5066/F7P55KJN) and 

click on “Site Information” on the main NWIS and site inventory pages. Then, click on the “Site Name” checkbox under 

“Site Identifier,” and click “Submit.” Enter “16783” in the 

“Site Name” field and choose the option button “match any 

part;” then click “Submit.” A search will be completed, and a 

resulting list of site numbers will appear. In the “Site Number”

column, click on the site number link, and then click on the 

“Field groundwater-level measurements” link. Use the dropdown menu beside “Available data for this site” and the links 

under “Output formats” to retrieve the desired data.

References Cited

Esri, 2015, ArcMap 10.4.1: Redlands, Calif., Esri, software. 

[Also available at http://desktop.arcgis.com/en/arcmap/10.4/

get-started/main/get-started-with-arcmap.htm.]

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.

National Oceanic and Atmospheric Administration, 2016, 

NCEI Hurricane Sandy digital elevation models: National 

Centers for Environmental Information, digital data, 

accessed January 8, 2016, at https://www.ngdc.noaa.gov/

mgg/inundation/sandy/sandy_geoc.html.

U.S. Geological Survey, 2017, USGS water data for the 

Nation: U.S. Geological Survey data release, accessed 

August 18, 2017, at https://doi.org/10.5066/F7P55KJN.
For more information about this report, contact:

Director, New York Water Science Center

U.S. Geological Survey

2045 Route 112, Building 4

Coram, NY 11727

dc_ny@usgs.gov

(518) 285–5602

Or visit our website at https://ny.water.usgs.gov

Publishing support provided by the 

Pembroke, Reston, and Rolla Publishing Service Centers
Como and others—Water-Table and Potentiometric-Surface Altitudes in Aquifers, Long Island, New York, April–May, 2016—Scientific Investigations Map 3398

ISSN 2329-132X (online) 

https://doi.org/10.3133/sim3398