Long Island Expwy

Middle Country Rd

Sunrise Hwy

Will ai m F ol yd Pkwy

Middle Country Rd

Long Island Expwy

Sunrise Hwy

West Main St

Main Rd

Main Rd

Main Rd

Sunrise Hwy

Montauk Highway

Montauk Hwy

Montauk Hwy

Montauk Hwy

Medford Rd

Patchogue - Yaphank Rd

Nesconset Rd

Patchogue - Port Jefferson Rd

Main St

Rocky Po ni t Rd

Sound Ave

Sound Avenue

Parker Road

Nugent Dr

Moriches - Riverhead Rd

Roanoke Ave

East Main St

Cross River Dr

Riverhead - Quogue Rd

Sound Ave

Montauk Hwy

Port Jefferson - West Hampton Rd

O dl Riverhead Rd

Lewis Rd

Montauk Hwy

Riverhead - Hampton Bays Rd

Montauk Hwy

(Hill St)

Ferry Rd

South Ferry Rd

Hampton St

Sag Harbor Tpke

Main St

William

Floyd Pkwy

Yaphank -

M di d el Island Rd

Gowanus Expwy

Belt Pkwy

(Shore Pkwy)

Belt Pkwy

(Shore Pkwy)

Belt Pkwy

(Shore Pkwy)

Belt Pkwy

Van Wyck Expwy

Cross Island Pkwy Sunrise Hwy

Southern State Pkwy

Brooklyn - Queens Expressway

Long Island Expwy

Queens Blvd

Grand Central Pkwy

Whitestone Expwy

Van Wyck Expwy

Linden Blvd

Clearview Expwy

Cross Island Pkwy

Jericho Tpke

Long Island Expwy

Meadowbrook State Pkwy

Jericho Turnpike

Jericho Tpke

Long Island Expwy

Wantagh State Pkwy

Seaford - Oyster Bay Expwy

Northern State Pkwy

Loop Pkwy

Meadowbrook State Pkwy

Sunrise Hwy

Ocean Pkwy

Wantagh State Pkwy

Southern State Pkwy

Southern State Pkwy

Sunrise Hwy

Ocean Pkwy

Robert Moses Twin Causeway

Jericho Tpke

Northern State Pkwy

Long Island Expwy

Sunken Meadow State Pkwy

Sagt ki os State Parkway

Southern State Pkwy

Heckscher State Pkwy

Long Island Expwy

Middle Country Rd

Ocean Pkwy

Kings Highway Flatbush Ave

Prospect Ave

Flatbush Avenue

Broadway

Eastern Parkway

Bay Pkwy

Northern Blvd

Woodhaven Blvd

Union Tpke

Myrtle Ave

Myrtle Ave

Cross Bay Blvd

Rockaway Blvd

Linden Blvd

Hillside Ave Rockaway Blvd

Merrick Blvd

Utop ai Pkwy

Northern Blvd

Northern Blvd

Middle Neck

Franklin Ave

Hempstead Tpke

Merrick Rd

Lido Blvd

Peninsula Blvd

Merrick Rd

Newbr di ge Rd

Hempstead Tpke

Port Washington Blvd

Hicksville Rd

Northern Blvd

Jer ci ho - Oyster Bay Rd

Cedar Swamp Rd

Montauk Hwy

New York Ave

Deer Park Ave

New York Ave

Northern Blvd

Northern Blvd

Elwood Rd

Wheeler Rd

Veterans Memorial Hwy

Hauppauge Rd

North Country Rd

Nesconset - Port Jefferson Hwy

Stony Brook Rd

Car el ton Ave

Smithtown Ave

Montauk Hwy

Sunrise Hwy

Veterans Memorial Hw

No

y

rthern State Pkwy

Jamaica Ave

Hillside Ave

Union Tpke

Grand Central Pkw

Lon

y

g Island Expwy

Rd

ATLANTIC OCEAN

LOWER

NEW YORK

BAY

UPPER

NEW YORK

BAY

SMITHTOWN

BAY

JAMAICA

BAY

EAST

RIVER

NORTHPORT

BAY HUNTINGTON

BAY

OYSTER

BAY

HARBOR

MANHASSET 

BAY

LITTLE

NECK

BAY

COLD

SPRING

HARBOR

HEMPSTEAD 

HARBOR

FLUSHING

BAY

HUDSON

RIVER

EAST

BAY

LONG

ISLAND

SOUND

NICOLL

BAY

LONG ISLAND SOUND

ATLANTIC OCEAN

BLOCK ISLAND 

SOUND

GARDINERS

BAY

GREAT

PECONIC

BAY

NAPEAGUE

BAY

LITTLE

PECONIC

BAY

NOYACK

BAY

MORICHES

BAY

SHINNECOCK

BAY

NORTHWEST

HARBOR

THREE

 MILE 

HARBOR

ORIENT

HARBOR

SOUTHOLD

BAY

HOG

NECK

BAY

CUTCHOGUE

HARBOR

MECOX

BAY

FLANDERS

BAY

TIANA

BAY

BELLPORT 

BAY PATCHOGUE 

BAY

GREAT SOUTH BAY

SOUTH

OYSTER

BAY

SHELTER ISLAND SOUND

NEW YORK

NEW YORK

COUNTY

HUDSON

COUNTY

BRONX COUNTY

RICHMOND

COUNTY

WESTCHESTER

COUNTY

KINGS

COUNTY

QUEENS

COUNTY

NEW YORK

NEW JERSEY

NEW YORK

NEW JERSEY

NEW YORK

NEW YORK COUNTY

SUFFOLK COUNTY

KINGS COUNTY

NEW YORK COUNTY

QUEENS COUNTY

BRONX COUNTY

QUEENS COUNTY

NASSAU COUNTY

BRONX COUNTY

WESTCHESTER COUNTY

BRONX COUNTY

WESTCHESTER COUNTY

NASSAU COUNTY

CONNECTICUT

NEW YORK

FAIRFIELD COUNTY

NASSAU COUNTY

CONNECTICUT

SUFFOLK COUNTY

NASSAU COUNTY

SUFFOLK COUNTY

NASSAU COUNTY SUFFOLK COUNTY

NASSAU COUNTY

NASSAU COUNTY

QUEENS COUNTY

QUEENS COUNTY

NASSAU COUNTY

QUEENS COUNTY

KINGS COUNTY

KINGS COUNTY

QUEENS COUNTY

NEW YORK COUNTY

HUDSON COUNTY RICHMOND COUNTY KINGS COUNTY

NASSAU 

COUNTY

SUFFOLK COUNTY

CONNECTICUT

NEW HAVEN COUNTY

NEW JERSEY

NEW YORK

NEW JERSEY

NEW YORK

-74° -73°30' -73° -72°30' -72°

-74° -73°30' -73° -72°30' -72°

40°50'

40°40'

40°30'

41°10'

41°

40°50'

10 0 10 MILES

10 0 10 KILOMETERS

SCALE=1:125,000

NEW YORK

CONNECTICUT

NEW JERSEY

Long Island

ATLANTIC OCEAN

20 0 20 KILOMETERS

20 0 20 MILES

U.S. Department of the Interior

U.S. Geological Survey

Base from U.S. Geological Survey digital data 1:100,000 series

Lambert Conformal Conic projection

Standard parallels 40° 40' N and 41° 2' N, central meridian 74° 00' W

North American Datum of 1983 Water-Table and Potentiometric-Surface Altitudes in the Upper Glacial, Magothy, and Lloyd Aquifers of Long Island, New York, April–May 2013

By

Michael D. Como, Michael L. Noll, Jason S. Finkelstein, Jack Monti, Jr., and Ronald Busciolano

2015

Hydrology by Michael Como

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

Nassau Suffolk Water Commissioners Association

New York State Department of Environmental Conservation

Sands Point Water Department

Suffolk County Water Authority

Water Authority of Great Neck North

Prepared in cooperation with the 

For additional information write to:

Director, U.S. Geological Survey, 2045 Route 112, Coram, NY 11727

Copies of this report are available on-line at http://ny.water.usgs.gov

ISSN 2329-132X (online)

http://dx.doi.org/10.3133/sim3326

Suggested citation: 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 sh., 

http://dx.doi.org/10.3133/sim3326.

5

25

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20

35

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45

50

55

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-5 0

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-10

5 0

10

N 12321

22.50

N 12232

8.04

N 12209

12.16

N 12318

6.21

N 6282

-14.25

Q 562

10.48

Q 3069

11.10

N 8354

11.61

N 1802

14.09

N 1328

16.16

N 9308

13.89

N 12191

16.69

N 1715

13.07

K 2859

7.21

K 1057

5.87

K 3410

8.80

Q 3627

17.38

Q 577

10.38

Q 283

11.02

Q 34

9.10

Q 3593

6.59

N 13879

6.00

N 13559

11.81

N 13700

6.76

N 6701

9.06

N 13682

8.62

N 11573

7.96

N 67

12.66

N 7

12.46

N 11580

11.58

N 11570

20.09

N 12450

14.96

N 11457

29.05

N 11455

34.59

N 12154

17.21

N 11730

-3.74

N 12523

20.05

N 11574

21.81

N 12082

18.12

N 4266

19.71

N 11453

49.48

N 10192

13.15 N 12507

22.52

N 12134

11.59

N 12076

2.81

N 12013

8.47 N 110

20.53

N 12508

10.93 N 12506

18.17

N 8046

3.60

N 11798

30.28 N 12075

38.62

N 12190

6.17

N 13596

35.32

N 11279

23.24

N 12646

24.98

N 12733

21.97

N 7152

3.84

S 21091

19.71

S 52162

22.92

S 33379

37.25

S 34743

18.13

S 6434

31.64

S 9

14.47

S 82938

16.86

N 12793

12.63

 Lloyd and North Shore Aquifers

 The Lloyd aquifer of upper Cretaceous age is the basal unit of Long Island’s 

groundwater system. This aquifer continuously underlies most of Long Island and the 

offshore waters, except in parts of western and northern 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, 1989). Aquifer thickness ranges from zero in northern and western 

parts of 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 2013 in 66 wells screened in the 

Lloyd and North Shore aquifers. Wells screened in the Pleistocene deposits of the North 

Shore aquifer in northern Nassau County are included because in these areas the North 

Shore aquifer is hydraulically connected to the Lloyd aquifer (Stumm, 2001; Stumm and 

others, 2002 and 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 in 2013 

ranged from about 14 ft below NGVD 29 in northwestern Nassau County to more than 49 ft 

above NGVD 29 in northeastern Nassau County. In Kings County, 3 measurements ranged 

from 5.87 to 8.80 ft; in Queens County, 7 measurements ranged from 6.59 to 17.38 ft; in 

Nassau County, 49 measurements ranged from -14.25 to 49.48 ft; and in Suffolk County, 7 

measurements ranged from 14.47 to 37.25 above NGVD 29.

Line of equal potentiometric-surface altitude—

 Shows altitude at which the water level would have stood in 

 tightly cased wells, April–May 2013.

 Solid where approximately known; dashed where inferred. 

 Contour interval 5 feet. Datum is NGVD 29. 

20

Inferred extent of the Lloyd aquifer

 

Inferred extent of the North Shore aquifer

 

S 58922

2.55

Monitoring well—Purple circle indicates observation well screened 

 in the Lloyd aquifer; purple circle with thick border indicates supply 

 well screened in the Lloyd aquifer; green circle indicates observation 

 well screened in the North Shore aquifer. Upper number is well number 

 assigned by the New York State Department of Environmental Conservation; 

 lower number is potentiometric-surface altitude in feet, NGVD 29.

EXPLANATION

400 feet 

0 feet 

Land surface topography—Shows land surface altitude in feet, NAVD 88.

300

200

100

Scientific Investigations Map 3326

Potentiometric surface in the Lloyd and North Shore aquifers—SHEET 3 of 4

Water-Table and Potentiometric-Surface Altitudes in the Upper Glacial, Magothy, and Lloyd Aquifers of Long Island, New York, April–May 2013

References Cited

Smolensky, D.A., Buxton, H.T., and Shernoff, P.K., 1989, Hydrologic framework of Long

 Island, New York: U.S. Geological Survey Hydrologic Investigations Atlas HA–709,

 3 sheets, scale 1:250,000.

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.

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.

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.

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.

Date

Oct. 2012

Nov. 2012 Dec. 2012

Jan. 2013

Feb. 2013

Mar. 2013

Apr. 2013May 2013

June 2013

July 2013

Aug. 2013

Sept. 2013

-10.0

-5.0

0.0

5.0

10.0

15.0

Daily altitude (NGVD 29), in feet

USGS 404943073414701 N 12508

Daily mean altitude (NGVD 1929)

Water level shown on map (NGVD 1929)

EXPLANATION

Date

Oct. 2012

Nov. 2012 Dec. 2012

Jan. 2013

Feb. 2013

Mar. 2013

Apr. 2013May 2013

June 2013

July 2013

Aug. 2013

Sept. 2013

5.0

0.0

10.0

15.0

20.0

25.0

Daily altitude (NGVD 29), in feet

USGS 404931073382101 N 110

Daily mean altitude (NGVD 1929)

Water level shown on map (NGVD 1929)

EXPLANATION

Date

Oct. 2012

Nov. 2012 Dec. 2012

Jan. 2013

Feb. 2013

Mar. 2013

Apr. 2013May 2013

June 2013

July 2013

Aug. 2013

Sept. 2013

25.0

30.0

35.0

40.0

45.0

50.0

Daily altitude (NGVD 29), in feet

USGS 404935073055901 S 33379

Daily mean altitude (NGVD 1929)

Water level shown on map (NGVD 1929)

EXPLANATION

NO DATA