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History and Hydrologic Effects of GroundWater Use in Kings, Queens, and Western 

Nassau Counties, Long Island, New York, 

1800’s through 1997 

By Richard A. Cartwright

___________________________________________________________

U.S. GEOLOGICAL SURVEY

Water-Resources Investigations Report 01-4096

In cooperation with 

NEW YORK CITY DEPARTMENT 

OF ENVIRONMENTAL PROTECTION

Coram, New York

2002
U.S. DEPARTMENT OF THE INTERIOR

Gail A. Norton, Secretary

U.S. GEOLOGICAL SURVEY

For additional information write to: Copies of this report can be purchased

from:

U.S. Geological Survey

Branch of Information Services

Box 25286 

Denver, CO 80225-0286

The use of firm, trade, and brand names in this report is for identification purposes 

only and does not constitute endorsement by the U.S. Geological Survey.

Charles G. Groat, Director

Sub-District Chief

U.S. Geological Survey

2045 Route 11, Bldg. 4

Coram, NY 11727

ii
Contents III

CONTENTS

Abstract.................................................................................................................................................................................. 1

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

Historical background.................................................................................................................................................. 2

Previous investigations ................................................................................................................................................ 3

Purpose and scope ....................................................................................................................................................... 3

Acknowledgments ....................................................................................................................................................... 4

Study area .............................................................................................................................................................................. 4

Hydrogeologic setting.................................................................................................................................................. 4

Depositional history..................................................................................................................................................... 4

Hydrostratigraphy........................................................................................................................................................ 5

Pleistocene deposits........................................................................................................................................... 5

Upper Pleistocene deposits...................................................................................................................... 5

Gardiners Clay......................................................................................................................................... 5

Jameco gravel .......................................................................................................................................... 5

Upper Cretaceous deposits ................................................................................................................................ 6

Magothy Formation and Matawan Group ............................................................................................... 6

Clay member of the Raritan Formation................................................................................................... 7

Lloyd sand member of the Raritan Formation......................................................................................... 7

Data collection....................................................................................................................................................................... 7

Monitoring-well installation ........................................................................................................................................ 7

Water-level measurements ........................................................................................................................................... 9

Ground-water sampling ............................................................................................................................................... 9

Geophysical logging .................................................................................................................................................... 9

History and hydrologic effects of ground-water development .............................................................................................. 9

Water-supply practices and their effects on the hydrologic system............................................................................. 13

Historical ground-water levels..................................................................................................................................... 13

Recent (1992-97) hydrogeologic conditions ......................................................................................................................... 13

Ground-water withdrawals .......................................................................................................................................... 17

Public supply ..................................................................................................................................................... 17

Industrial supply ................................................................................................................................................ 17

Dewatering......................................................................................................................................................... 17

Ground-water inputs .................................................................................................................................................... 18

Precipitation....................................................................................................................................................... 18

Leaky sewer lines and water mains ................................................................................................................... 18

Ground-water levels..................................................................................................................................................... 18

Upper glacial aquifer ......................................................................................................................................... 18

Jameco-Magothy aquifer ................................................................................................................................... 20

Lloyd aquifer ..................................................................................................................................................... 24

Ground-water quality................................................................................................................................................... 26

Chloride ............................................................................................................................................................. 27

Upper glacial aquifer ............................................................................................................................... 29

Jameco-Magothy aquifer ......................................................................................................................... 36

Lloyd aquifer ........................................................................................................................................... 46

Nitrate ................................................................................................................................................................ 52

Upper glacial aquifer ............................................................................................................................... 52

Jameco-Magothy aquifer ......................................................................................................................... 54

Lloyd aquifer ........................................................................................................................................... 57

Organic compounds........................................................................................................................................... 58
IV Contents

Public-supply wells ................................................................................................................................. 59

Monitoring wells ..................................................................................................................................... 64

Revised hydrogeologic framework ............................................................................................................................. 75

Upper glacial aquifer......................................................................................................................................... 75

Gardiners Clay .................................................................................................................................................. 75

Jameco aquifer .................................................................................................................................................. 75

Magothy aquifer................................................................................................................................................ 75

Raritan clay and Lloyd aquifer.......................................................................................................................... 75

Summary and conclusions .................................................................................................................................................... 75

References cited .................................................................................................................................................................... 78

FIGURES

1-15. Maps showing:

1. Location of Kings, Queens, and western Nassau Counties, Long Island, N.Y. .............................................................. 2

2. Hydrogeologic section through Kings and Queens counties, N.Y. ................................................................................. 6

3. Water-table configuration in Kings, Queens, and western Nassau Counties, N.Y., in: A. 1903. B. 1936. C. 1943. 

D. 1951. E. 1961. F. 1974. G. 1981. H. 1983. I. 1997.................................................................................................... 19

4. Ground-water levels in 1983 and 1996 at wells screened in the Jameco-Magothy aquifer in Kings, Queens, and 

western Nassau Counties, N.Y. ...................................................................................................................................... 28

5. Ground-water levels in 1983 and 1996 at wells screened in the Lloyd aquifer in Kings and Queens Counties, N.Y. ... 29

6. Locations of wells screened in the upper glacial, Jameco-Magothy, and Lloyd aquifers in Kings, Queens, and 

western Nassau Counties, N.Y., from which ground-water samples were collected in 1983 through 1996. 

A. Upper glacial aquifer wells sampled in 1983. B. Jameco-Magothy aquifer wells sampled in1983. C. Lloyd 

aquifer wells sampled in 1983. D. Upper glacial aquifer wells sampled in 1992. E. Jameco-Magothy aquifer 

wells sampled in 1992. F. Lloyd aquifer wells sampled in 1992. G. Upper glacial aquifer wells sampled in 

1995-96. H. Jameco-Magothy aquifer wells sampled in 1995-96. I. Lloyd aquifer wells sampled in 1995-96 ......... 30

7. Chloride concentration in the upper glacial aquifer in Kings, Queens, and western Nassau Counties, N.Y. A. 1947. 

B. 1961. C. 1970. D. 1981. E. 1983. F. 1992. G. 1995-96 ........................................................................................ 39

8. Chloride concentration in the Jameco-Magothy aquifer in Kings, Queens, and western Nassau Counties, N.Y. 

A. 1983. B. 1992. C. 1996............................................................................................................................................ 46

9. Chloride concentration in the Lloyd aquifer in Kings, Queens, and western Nassau Counties, N.Y. A. 1983. 

B. 1992. C. 1996............................................................................................................................................................ 49

10. Nitrate concentration in the upper glacial aquifer in Kings, Queens, and western Nassau Counties, N.Y. A. 1983. 

B. 1992. C. 1996............................................................................................................................................................. 53

11. Nitrate concentration in the Jameco-Magothy aquifer in Kings, Queens, and western Nassau Counties, N.Y. 

A. 1983. B. 1992. C. 1996.............................................................................................................................................. 56

12. Nitrate concentration in the Lloyd aquifer in Kings, Queens, and western Nassau Counties, N.Y. A. 1983. B. 1992. 

C. 1996 ........................................................................................................................................................................... 59

13. Locations of public-supply wells in Queens and western Nassau Counties, N.Y., at which volatile organic compounds 

were detected in 1992. A. Wells screened in the upper glacial aquifer. B. Wells screened in the Jameco-Magothy or 

Lloyd aquifers................................................................................................................................................................. 62

14. Locations of public-supply wells in Queens and western Nassau Counties, N.Y., at which volatile organic compounds 

and one pesticide were detected in 1996. A. Wells screened in the upper glacial aquifer. B. Wells screened in the 

Jameco-Magothy aquifer................................................................................................................................................ 64

15. Locations of monitoring wells in Kings, Queens, and western Nassau counties, N.Y., at which organic compounds 

were detected in 1992-93 and 1995................................................................................................................................ 73

TABLES

1. U.S. Geological Survey ground-water-quality sampling in Kings, Queens, and western Nassau Counties, N.Y., 

1981-96........................................................................................................................................................................... 4

2. Well-completion data for 37 new wells, Kings and Queens Counties, N.Y.................................................................... 8

3. Water samples collected from the monitoring-well network in Kings, Queens, and western Nassau Counies, N.Y., 

1983-96 .......................................................................................................................................................................... 10
Contents V

4. History and hydrologic effects of ground-water use in Kings and Queens Counties, N.Y., 1800’s-1996...................... 14

5. Concentrations of selected volatile organic compounds in water from public-supply wells in Queens County, 

N.Y., 1992 ....................................................................................................................................................................... 66

6. Concentrations of selected volatile organic compounds in water from public-supply wells in Nassau County, 

N.Y., 1992 ....................................................................................................................................................................... 69

7. Concentrations of selected volatile organic compounds in water from public-supply wells in Queens County, 

N.Y., 1996 ....................................................................................................................................................................... 70

8. Concentrations of selected volatile organic compounds and one pesticide in water from public-supply wells in 

Nassau County, N.Y., 1996............................................................................................................................................. 71

9. Monitoring wells in Kings, Queens, and Nassau Counties, N.Y., at which organic constituents were detected in 

ground water, 1996 ......................................................................................................................................................... 72

10. Revised hydrogeologic framework for Kings and Queens Counties, N.Y...................................................................... 74

CONVERSION FACTORS, ABBREVIATIONS AND VERTICAL DATUM

Sea level: In this report, “sea level” refers to the National Geodetic Vertical Datum of 1929 (NGVD of 

1929)--a geodetic datum derived from a general adjustment of the first-order level nets of the 

United States and Canada, formerly called Sea Level Datum of 1929.

Multiply By To Obtain

Length

inch (in) 25.40 millimeter

foot (ft) 0.3048 meter

mile (mi) 1.609 kilometer

Area

square mile (mi2) 2.59 square kilometer

Flow

million gallons per day (Mgal/d) 0.0438 cubic meters per second

Hydraulic conductivity

foot per day (ft/d) 0.3048 meter per day

Other abbreviations used in this report

micrograms per liter (μg/l)

milligrams per liter (mg/L)

millisiemens per meter (mS/m)
This page has been left blank intentionally.
Introduction 1

History and Hydrologic Effects of Ground-Water Use 

in Kings, Queens, and Western Nassau Counties, 

Long Island, New York, 1800’s through 1997

By Richard A. Cartwright

Abstract

Ground-water withdrawals from the aquifers 

underlying Kings and Queens Counties varied 

temporally and spatially during the 20th century 

and caused extreme changes in water levels. The 

resultant lowering of water levels during periods 

of heavy pumping caused saltwater intrusion in 

nearshore areas and the migration of contaminants 

from land surface into deep aquifers. The recovery 

of water levels in response to countywide 

curtailment of pumping has resulted in the 

flooding of underground structures. Combined 

withdrawals for public and industrial supply in 

Kings and Queens Counties were greatest during 

the 1930’s—about 130 million gallons per day. 

During this period, a large cone of depression 

developed in the water table in Kings County; 

within this depression, water levels were about 

45 feet lower than in 1903. All pumping for public 

supply was halted in Kings County in 1947, and in 

Jamaica (in Queens County) in 1974. Water levels 

in Kings County had recovered by 1974 and have 

remained similar to those of 1903 since then, 

except for minor localized drawdowns due to 

industrial-supply or dewatering withdrawals. A 

large cone of depression that had formed in 

southeastern Queens County before 1974 has now 

(1997) disappeared. The estimated combined 

withdrawal for public supply and industrial supply 

in Kings and Queens Counties in 1996 was only 

about 50 million gallons per day.

The water-level recoveries in the water-table 

and confined aquifers generally have resulted in 

the dilution and dispersion of residual salty and 

nitrate-contaminated ground water. The majority 

of recently sampled wells indicate stable or 

decreasing chloride and nitrate concentrations in 

all aquifers since 1983. Organic contaminants 

remain in ground water in Kings, Queens, and 

Nassau Counties, however; the most commonly 

detected compounds in 1992-96 were 

tetrachloroethene, trichloroethene, chloroform, 

and total trihalomethanes. Water samples from 

monitoring wells in Kings County indicate a 

greater number of occurrences of these 

compounds in the upper glacial aquifer than in the 

Jameco-Magothy aquifer, whereas samples from 

public-supply wells in Queens County indicated a 

greater number of occurrences in the JamecoMagothy aquifer than in the upper glacial aquifer. 

This distribution suggests that organic 

contaminants were not drawn into the deeper 

aquifers in Kings County before 1947, when their 

use was limited and deep withdrawals were 

greatest, and (or) that the longer period of waterlevel recovery in Kings County than in Queens has 

allowed greater degradation, dilution, and 

dispersion of any organic contaminants that might 

have entered the deep aquifers before the cessation 

of pumping in 1947.

INTRODUCTION

Most of the water used by the 4.25 million 

inhabitants of Kings and Queens Counties, on western 

Long Island, N.Y. (fig. 1) (U.S. Department of 

Commerce, 1990) is surface water derived from an 

upstate reservoir-and-tunnel system owned and 

operated by the New York City Department of 

Environmental Protection (NYCDEP). In 1991, this 

system supplied an average of 1,445.5 Mgal/d to New 
2 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

York City’s five boroughs—Manhattan, Brooklyn 

(Kings County), Queens (Queens County), Bronx, and 

Staten Island; about 412 Mgal/d was supplied to Kings 

County and about 304 Mgal/d to Queens County (New 

York City Department of Environmental Protection, 

1992) and supplied an additional 123.6 Mgal/d to 

other upstate communities. The remaining watersupply requirements of Kings and Queens Counties 

are met by ground-water withdrawals from a single 

public-supply wellfield in Queens County, formerly 

owned by the Jamaica Water Supply Company (JWS), 

now owned and operated by the NYCDEP. Watersupply managers are concerned that the surface-water 

reserves may be insufficient to meet the City’s demand 

during periods of drought or other water-supply 

emergencies and that alternative sources of potable 

water will be needed (New York City Department of 

Environmental Protection, 1992). One possible source 

is ground water from Kings and Queens Counties.

Historical Background

Trends in ground-water use on western Long 

Island (Kings and Queens Counties) have been 

variable throughout the 20th century, and the groundwater reservoir has been subjected to a wide range of 

pumping practices as water demands have increased. 

In the past, high rates of withdrawal resulted in 

extremely large drawdowns of the water table and in 

large declines in potentiometric heads of underlying 

aquifers. The development and completion of sanitary 

sewer systems during the 1930’s caused additional 

losses from the ground-water system by diverting the 

return flow of wastewater to coastal water bodies. By 

40°45'

74°00' 73°45'

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York–New Jersey–Connecticut,1984;

Newark, New Jersey–New York, 1986

Rockaway

Point

Coney Island

Rockaway Peninsula

Long Beach

LOCATION MAP

NEW YORK

STUDY

AREA

Long Island

Atlantic Ocean

East

River

Flushing Bay

JamaicaBay

Flushing

Creek

Alley Pond

Creek

Hudson River

New

York

Bay

The Narrows

New

Cre

town

ek

Little Neck

Bay

Far

Rockaway

Manhattan

Barrier Beach

KINGS COUNTY

QUEENS COUNTY

NASSAU

COUNTY

New York

County

New

Jersey

01234 5 MILES

0 1234 5 KILOMETERS A'

Flatbush

Franchise

Area

AREA SHOWN IN

FIGS. 13 AND 14

Woodhaven

Franchise Area

Jamaica Franchise

Area

A

AREA SHOWN IN

FIGS. 3-12 & 15

East

New

York

Figure 1. Location of Kings, Queens, and western Nassau Counties, Long Island, N.Y.
Introduction 3

1936, water levels in northern Kings County had 

declined as much as 45 ft below 1903 levels, and, by 

1961, water levels in southern Queens County had 

declined as much as 35 ft. The decline in water levels 

caused natural seaward flow gradients to reverse in 

some areas, inducing saltwater intrusion and local 

ground-water contamination, which, in turn, 

necessitated the shutdown of all public-supply wells in 

Kings County and some in Queens County. The 

cessation of pumping allowed the severely depressed 

water table to recover, and the rising water levels in 

some areas ultimately began to flood manmade 

subterranean structures, such as basements and 

subway tunnels that had been built during the period 

when the water table was depressed. As a result, many 

basements and subway tunnels in Kings County today 

require nearly continuous dewatering. This series of 

events has been the focus of several investigations 

throughout western Long Island. A summary of 

ground-water development in Kings and Queens 

Counties from 1900 through 1981 is given in Buxton 

and others (1981). 

The present investigation began in April 1992 as a 

4-year study in cooperation with the NYCDEP that 

was designed, in part, as an update to a similar 

investigation completed in the early 1980’s (Buxton 

and Shernoff, 1995). The main objectives of the 

Buxton and Shernoff study were to (1) define groundwater quality in the aquifer system of Kings and 

Queens Counties (hereafter referred to as the KingsQueens aquifer system) with emphasis on the 

concentrations and distribution of nitrate, chloride, 

and to a lesser degree, volatile organic compounds 

(VOC’s); (2) establish a hydrologic-data-collection 

network in Kings and Queens Counties that would 

include ground-water-level and streamflow 

measurements, and (3) estimate the effects of current 

and proposed water-supply and dewatering operations 

on ground-water levels and flow in the Kings-Queens 

aquifer system through numerical model simulation.

Previous Investigations

The earliest USGS investigations of the geology 

and ground-water resources of Long Island include 

Veatch and others (1906), Fuller (1914), Suter (1937), 

Suter and others (1949), and Cohen and others (1968). 

Subsequent investigations that have examined specific 

aspects of the ground-water system, including watertable fluctuations and ground-water quality, are 

described in Lusczynski (1952), Lusczynski and 

Spiegel (1954), Perlmutter and others (1959), 

Perlmutter and Geraghty (1963), Perlmutter and Soren 

(1962), Lusczynski and Swarzenski (1966), and Soren 

(1971, 1976, and 1978). 

Studies by the USGS, NYCDEP, and New York 

State Department of Environmental Conservation 

(NYSDEC) were precursors to the present study. 

These include Buxton and others (1981), Holzmacher, 

McLendon & Murrell (1982), Buxton and Shernoff 

(1995), O’Brien and Gere and New York City 

Department of Environmental Protection (1986), 

Austin and others (1988), Buxton and Smolensky 

(1999), and Buxton and others (1999). Buxton and 

others (1981) designed a ground-water-sampling 

network from which a water-quality data base was 

developed; available wells from this network were 

used for water-quality analyses during the 1983 

investigation (Buxton and Shernoff, 1995) and the 

present study. A ground-water-flow model of Buxton 

and Smolensky (1999) was refined and updated in the 

present study to provide more detailed simulations of 

the effects of ground-water withdrawals on the KingsQueens aquifer system.

Several aspects of the present study are described 

in other reports; these include the collection of 

ground-water-quality data (Cartwright and others, 

1998), the compilation of specific-capacity-test results 

(Chu, 1996), the compilation of historical pumpage 

records (Chu and others, 1997), the preliminary 

delineation of the freshwater-saltwater interface (Chu 

and Stumm, 1995), the development of a twodimensional model (Kontis, 1999) and a threedimensional model (Misut and Monti, 1999) of 

ground-water flow demonstrating the feasibility of 

using ground water as a supplemental water supply, a 

compilation of water-level measurements made in the 

study area from 1910 through 1995 (Monti, 1997), and 

a 1997 water-table map of Kings and Queens Counties 

(Monti and Chu, 1997).

Purpose and Scope

This report describes the recent (1992-97) 

hydrologic conditions (withdrawals, inputs, water 

levels, and water quality) in Kings, Queens, and 

western Nassau Counties, and compares them with 

historical data. The report also summarizes the 

relations among water-use practices, and ground-water 

levels and ground-water quality. The hydrogeologic 
4 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

framework of western Long Island is revised, and a list 

of wells sampled for water quality during 1981-96 is 

provided. USGS water-quality sampling in Kings, 

Queens, and western Nassau Counties during 1981-96 

is summarized in table 1; the data indicate the attrition 

of wells available for sampling during that period.

Acknowledgments

The author thanks Richard Gainer, Michael P. 

Rennard, Joseph Iannuzzi, Anthony Bellitto, Jr., and 

Edmund Parrish of the NYCDEP Bureau of Water 

Supply and Wastewater Management for providing 

information used during the investigation. Thanks also 

are extended to Thomas Attridge (President) and 

Richard Groth (Superintendent) of Maple Grove 

Cemetery for their cooperation during well installation 

on cemetery property; to Julius Spiegel and Michael 

Siegel (New York City Department of Parks and 

Recreation, Brooklyn), Mary Fox (Prospect Park 

Alliance), Ronald Cianciulli and Peter Mantione (New 

York City Department of Parks and Recreation, 

Queens), and Richard Ocken (New York City 

Department of Transportation, Highways) for 

permission to drill and for assistance with drill-site 

selection on City property. The author also is grateful 

to Alfonso R. Lopez of the NYCDEP Bureau of Clean 

Water for permission to store drill rigs on waterpollution-control plant properties.

STUDY AREA

The study area represents all of Kings and 

Queens Counties and the western part of Nassau 

County (fig. 1). This area encompasses about 261 mi2

, 

of which Kings County occupies about 76 mi2, 

Queens County about 113 mi2, and western Nassau 

County about 72 mi2

. The study area is bounded to the 

west, north, and south by The Narrows, New York Bay, 

the East River, Long Island Sound, and the Atlantic 

Ocean, and on the east by the remainder of Nassau 

County. The entire study area is densely populated and 

includes scattered parks and cemeteries, industrial and 

commercial areas, and transportation facilities.

Hydrogeologic Setting

Long Island consists of a sequence of 

unconsolidated, Pleistocene and Cretaceous deposits 

that lie unconformably on Precambrian bedrock. Total 

sediment thickness in the study area ranges from about 

100 ft in the northwest (except in northwestern Queens 

County where bedrock crops out) to about 1,000 ft in 

the southeast. Most of the sediments in northern Kings 

and Queens Counties are Pleistocene deposits, 

whereas the bulk of the deposits in the rest of the study 

area is of Cretaceous age.

Depositional History

The depositional history of the study area is, with 

minor exceptions, typical for all of Long Island. The 

Precambrian bedrock surface was eroded to a nearly 

horizontal plain over much of the eastern United 

States by Silurian or early Cretaceous time. The timing 

of this erosion cannot be determined because 

Paleozoic and Mesozoic deposits are absent above 

bedrock (Smolensky and others, 1989). A period of 

widespread folding followed, in which the mainland 

was uplifted and the coastal area was downwarped, 

causing the area of the present Long Island to be 

inundated. Streams from the highlands to the west 

Table 1. U.S. Geological Survey ground-water-quality sampling in Kings, Queens, and western Nassau Counties, 

N.Y., 1981-96

Sampling period

Number of

wells sampled

Percentage

of 1981 wells

sampled

Percentage

of 1983 wells

sampled

Percentage

of 1992-93

wells sampled Source of data

February-April 1981 78 100 0 0 Buxton and others (1981)

June-October 1983 106 68 100 0 Buxton and Shernoff (1995)

August 1992-January 1993 87 58 82 100 Cartwright and others (1998)

July-September 1995 21 0 0 0 Cartwright and others (1998)1

March-July 1996 101 46 70 84 Cartwright and others (1998)

1

New wells installed from November 1992 to October 1995.
Study Area 5

carried large volumes of sediment to the coast, where 

they formed the thick, deltaic deposits of Cretaceous 

age that underlie Long Island. During the Tertiary 

period, a series of sea-level changes resulted in 

alternating episodes of minor deposition and erosion 

offshore south of Long Island; whether these episodes 

occurred on Long Island is uncertain, however, 

because Tertiary deposits are not present onshore 

(Smolensky and others, 1989). The last erosional 

period, which may have been during late Pliocene 

time, generated many of the topographic features of 

Long Island, including the ancestral Long Island 

Sound and erosional scouring of a deep north-south 

channel in Queens County described by Soren (1978) 

as having been incised by an ancestral Hudson River 

system. During the Quaternary, Pleistocene glacial 

episodes and the resulting changes in sea level caused 

alternating periods of deposition and erosion that 

reworked the surficial sediments. The last major 

features to be formed on Long Island are the glacial 

moraines, which were emplaced during the 

Wisconsinan glacial stage, and outwash that was 

deposited south of the moraines by glacial meltwater. 

Hydrostratigraphy

The hydrostratigraphy of the study area is 

thoroughly discussed in reports cited in the reference 

section and is summarized by Buxton and Shernoff 

(1995). The following sections briefly outline the 

major stratigraphic units from the surface downward 

and their hydrologic properties within the study area. 

Major hydrogeologic units are depicted in figure 2.

Pleistocene Deposits

The Pleistocene deposits consist of three 

hydrogeologic units—the upper glacial aquifer, the 

Gardiners Clay, and the Jameco aquifer. These units 

form the thickest part of the sediment column in the 

northwestern part of the study area and are present in 

varying degrees throughout Kings, Queens, and 

western Nassau Counties.

Upper Pleistocene Deposits

The Upper Pleistocene deposits are present at the 

surface throughout most of the study area, except in 

parts of northwestern Queens County, where bedrock 

crops out. These deposits consist of two general types 

of Wisconsinan-aged glacial deposits: (1) terminalmoraine and ground-moraine deposits, both of which 

consist of poorly sorted mixtures of clay, silt, sand, 

gravel, and boulders, and (2) glaciofluvial outwash 

deposits, which consist of moderately to well-sorted 

mixtures of sand and gravel. The thickness of these 

deposits ranges from zero where bedrock crops out to 

about 500 ft in buried valleys, but typically is 100 to 

200 ft. The Upper Pleistocene deposits form the upper 

glacial aquifer, which has a relatively high but locally 

variable permeability. The horizontal hydraulic 

conductivity of outwash deposits on Long Island is 

reported to be 270 ft/d (Franke and Cohen, 1972), but 

probably is half this value in poorly sorted moraine 

deposits (Buxton and Shernoff, 1995). The upper 

glacial aquifer, although generally unconfined, is 

confined locally by layers of silt and clay within the 

moraine deposits.

Gardiners Clay

This unit underlies Upper Pleistocene deposits 

and is present throughout most of Kings, southern 

Queens, and western Nassau Counties. The Gardiners 

Clay is described by Soren (1978) to have been 

deposited in lagoonal and marine environments during 

the Sangamon interglacial interval. The unit consists 

of greenish-gray clay and silt with interbedded sand; 

its thickness ranges from zero at the northern limit in 

northern Kings County and southwestern Queens 

County to more than 100 ft in southern parts of the 

study area. The Gardiners Clay has a vertical hydraulic 

conductivity of about 0.001 ft/d (Franke and Cohen, 

1972) and is a major confining unit.

Jameco Gravel

The Jameco Gravel is the oldest Pleistocene 

deposit on Long Island; its extent in the study area is 

similar to that of the Gardiners Clay. The Jameco 

Gravel was deposited as channel fill in a river-scour 

system described as part of an ancestral Hudson River 

channel (Soren, 1978). Thickness in the study area 

ranges from zero at the northern limit (northern Kings 

and southern Queens Counties) to more than 200 ft in 

the deepest part of the buried channel. The Jameco 

Gravel consists of dark, coarse sand and gravel with 

cobbles and boulders and constitutes the Jameco 

aquifer. Horizontal hydraulic conductivity of the 

Jameco aquifer exceeds 270 ft/d (Soren, 1971) and is 

among the highest of any unit in the study area.
6 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Geologic unit

 Upper Pleistocene deposits

 Gardiners clay

 Jameco gravel

 Magothy Formation and Matawan

 Group undifferentiated

 Unnamed clay member of the

 Raritan Formation

 Lloyd Sand Member of the

 Raritan Formation

QUATERNARY

Qu

Qg

Qj

Kmm

Krc

Krl

CRETACEOUS

EXPLANATION

VERTICAL EXAGGERATION X 30

200

SEA

LEVEL

–200

–400

–600

–800

–1,000

FEET

SEA

LEVEL

–200

–400

–600

–800

–1,000

FEET

KINGS CO.

QUEENS CO.QUEENS CO.

KINGS CO.

Jamaica Bay

Rockaway Inlet

Qu Qu

Qj

Krc

Krl

Kmm

Qg Qj

Qu

Krc

Bedrock

Qg

200

A A' East River

Atlantic Ocean

Upper Cretaceous Deposits

Upper Cretaceous deposits make up the bulk of 

the sediments in the southeastern part of the study 

area. These deposits dip to the southeast and consist of 

the Magothy Formation and Matawan Group, 

undifferentiated, and the unnamed clay and Lloyd 

Sand Members of the Raritan Formation.

Magothy Formation and Matawan Group

The Magothy Formation and Matawan Group, 

undifferentiated, generally is the thickest stratigraphic 

unit on Long Island but was partly removed from 

northwestern Long Island by extensive postCretaceous erosion. This unit is present in the southern 

halves of Kings and Queens Counties; its northern 

extent is irregular and poorly defined as a result of 

post-Cretaceous channel erosion. These deposits 

constitute the Magothy aquifer and consist mostly of 

light-colored quartzose sand and silty sand, with some 

interbedded clay. Thickness of this unit ranges from 

zero at its northern limits and along channel margins 

to more than 200 ft in southern Kings County, and to 

more than 500 ft in southeastern Queens County. As 

described in the “Depositional History” section, the 

most striking feature of this unit is the nearly 300-ftdeep erosional channel that was carved in Queens 

County during post-Cretaceous time by an ancestral 

diversion of the Hudson River (Soren, 1978). This 

channel subsequently was filled with Pleistocene 

Figure 2. Hydrogeologic section through Kings and Queens Counties, N.Y. (Modified from Buxton and Shernoff, 1999, pl. 2. 

Trace of section is shown in fig. 1.)
Data Collection 7

deposits. Horizontal hydraulic conductivity of the 

Magothy aquifer on Long Island is estimated to range 

from 60 to 90 ft/d (McClymonds and Franke, 1972) 

but can be much higher or lower locally, depending on 

sediment types. The Magothy aquifer and overlying 

Jameco aquifer (where present) are hydraulically 

connected and, therefore, commonly are considered as 

one hydrogeologic unit (Buxton and Shernoff, 1995). 

In this report, these units are jointly termed the 

Jameco-Magothy aquifer.

Clay Member of the Raritan Formation

The Clay Member of the Raritan Formation 

extends throughout most of Kings and Queens 

Counties and is the most extensive Cretaceous deposit 

in the study area. It is absent from northwestern Kings 

County and extreme northwestern Queens County and 

also has been eroded from the area of the buried 

channel described earlier. Thickness of the Clay 

Member ranges from zero in northwestern Kings and 

Queens Counties and along the margin of the buried 

channel to about 250 ft in southeastern Kings County 

and about 200 ft in southeastern Queens County. The 

Clay Member generally consists of clay and silty clay 

with some interbedded sand. Vertical hydraulic 

conductivity of this unit generally is estimated to be 

about 0.001 ft/d (Franke and Cohen, 1972). The terms 

“Clay Member of the Raritan Formation” and “Raritan 

clay” are used interchangeably in this report.

Lloyd Sand Member of the Raritan Formation

The Lloyd Sand Member of the Raritan 

Formation is the oldest Cretaceous deposit on Long 

Island and lies unconformably on Precambrian 

bedrock. It is absent from northern Kings and 

northwestern Queens Counties, and from the buried 

channel in Queens County. Thickness ranges from 

zero at its northern limit to about 200 ft in southeastern 

Kings County, and to about 300 ft in southeastern 

Queens County. The Lloyd Sand Member consists of 

quartz sand and gravel with interbedded silt and clay 

and constitutes the Lloyd aquifer. The Lloyd aquifer is 

confined by the Clay Member of the Raritan 

Formation (fig. 2), except locally along its 

northwestern margin, where the clay member is 

absent. Horizontal hydraulic conductivity of this unit 

on Long Island ranges from about 50 to 70 ft/d 

(McClymonds and Franke, 1972), but is higher in 

gravel and lower in clayey zones. The terms “Lloyd 

Sand Member” and “Lloyd aquifer” are used 

interchangeably in this report.

DATA COLLECTION

This study entailed monitoring-well installation, 

water-level measurements, ground-water sampling, 

and geophysical logging. Monitoring-well installation 

included the completion of 29 new monitoring wells 

and the incorporation of 8 other (not USGS) wells in 

the National Water Information System (NWIS). The 

placement of new wells was designed to provide 

water-level measurements and ground-water samples 

in areas where these data were sparse. Water-level 

measurements were collected from a network of more 

than 100 wells—initially on a monthly basis, then 

quarterly. Ground-water sampling was conducted 

during three different sampling periods to provide 116 

samples for chemical analysis for organic and 

inorganic compounds and nutrients. Chemical data are 

presented in Cartwright and others (1998); 

interpretations of these data are discussed here. 

Lithologic logs and down-hole geophysical logs from 

new well installations helped to refine the 

conceptualization of the hydrogeologic framework 

and, in some areas, to detect saltwater intrusion. 

Monitoring-Well Installation

A total of 29 new monitoring wells was installed 

from November 1992 through October 1995 (27 

drilled and installed by the USGS, and 2 drilled by the 

NYCDEP and cased by the USGS). Four wells were 

screened in the Lloyd aquifer, 3 in the Magothy 

aquifer, 4 in the Jameco aquifer, and 18 in the upper 

glacial aquifer.

Three drilling techniques were used for well 

installation. Augering was adequate for shallow wells 

in areas of outwash containing gravel, sand, silt or 

clay, but reverse mud-rotary and air-rotary methods 

were required in areas containing glacial moraine 

deposits, where cobbles and boulders were present. In 

addition to the 29 new wells, 8 other wells were 

installed by the Brooklyn Union Gas Company and 

NYCDEP; the drilling techniques used for these 

installations are not recorded. All new wells were 

assigned NYSDEC well-identification numbers and 

have been added to NWIS. Well-completion data for 

all 37 wells are given in table 2.
8 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Table 2. Well-completion data for 37 new wells, Kings and Queens Counties, N.Y.

[Well numbers assigned by New York State Department of Environmental Conservation. Prefix K, Kings County; 

Q, Queens County; --, data not available; BUG, Brooklyn Union Gas, well destroyed; USGS, U.S. Geological Survey, 

NYCDEP, New York City Department of Environmental Protection]

Well

number Latitude Longitude

Completion

date Aquifer

Depth of well,

in feet below

sea level

Top of open

interval, in

feet below

sea level

Bottom of

open interval,

in feet below

sea level Owner

K3405 403719 735733 09/15/94 Upper glacial 214 204 214 USGS

K3406a 403806 740219 09/08/94 Jameco 155 135 145 USGS

K3407 403520 735757 12/02/94 Jameco 405 385 405 USGS

K3410b 404039 735550 10/18/94 Lloyd 360 330 350 USGS

K3414 403431 735811 11/10/94 Magothy 410 390 410 USGS

K3423a 403806 740219 09/08/94 Upper glacial 38 18 38 USGS

K3424 403840 735921 09/17/93 Upper glacial 75 70 75 USGS

K3425b 404039 735550 11/19/92 Upper glacial 80 70 75 USGS

K3426 403952 735137 06/26/87 Lloyd 494 474 494 Private

K3430c 403941 735743 10/05/95 Upper glacial 120 100 110 USGS

K3431c 403941 735743 10/03/95 Magothy 385 355 375 USGS

Q3587e 404138 735351 10/11/94 Upper glacial 175 160 170 USGS

Q3589 404026 734721 09/29/94 Magothy 320 310 320 USGS

Q3593d 404733 734829 12/22/94 Lloyd 215 165 185 USGS

Q3604d 404732 734829 12/22/94 Upper glacial 58 48 58 USGS

Q3627f 404239 734930 06/05/95 Lloyd 510 480 500 USGS

Q3628f 404239 734929 06/15/95 Lloyd 340 310 330 USGS

Q3629f 404239 734928 06/18/95 Upper glacial 80 50 70 USGS

Q3644 404537 735458 -- Upper glacial 84 79 84 NYCDEP

Q3645 404534 735402 -- Upper glacial -- -- -- NYCDEP

Q3646 404544 735344 -- Upper glacial 24 19 24 NYCDEP

Q3647 404519 735325 -- Upper glacial 35 30 35 NYCDEP

Q3648 404437 735354 -- Upper glacial 90 80 85 USGS

Q3649e 404138 735351 11/18/92 Upper glacial 110 100 105 USGS

Q3650 404402 735209 04/07/93 Upper glacial 50 40 50 USGS

Q3651 404251 735126 11/20/92 Upper glacial 80 70 75 USGS

Q3652 404350 734945 11/17/92 Upper glacial 90 80 85 USGS

Q3653 403929 734930 -- -- -- -- -- BUG

Q3654 403916 734932 -- -- -- -- -- BUG

Q3655 403918 734940 -- -- -- -- -- BUG

Q3656 403928 734942 -- -- -- -- -- BUG

Q3657 403925 734934 06/09/89 Lloyd 695 608 650 BUG

Q3658 404027 734645 11/08/93 Upper glacial 40 30 35 USGS

Q3659 404313 734752 04/06/93 Upper glacial 125 115 120 USGS

Q3660 404450 734703 11/16/92 Upper glacial 90 80 85 USGS

Q3661 404357 734620 11/20/92 Upper glacial 95 85 90 USGS

Q3662 404500 734300 04/05/93 Upper glacial 120 110 115 USGS

a,b,c,d,e = well doublets

f = well triplet
History and Hydrologic Effects of Ground-Water Development 9

Most of the 37 new wells are constructed of either 

2-in or 4-in-diameter PVC casing and slotted screen 

with a 5-ft or 10-ft sump at the bottom. The five wells 

that required air-rotary drilling have an additional 

outside casing of 8-in-diameter steel that extends 75 to 

100 ft below land surface. Two of the new wells were 

designed with 1.25-in-diameter PVC pipe and slotted 

screen, which was placed in the annular space between 

the borehole, and a 2-in or 4-in-diameter PVC casing. 

Wells that were installed by mud- or air-rotary 

techniques were developed by air-lifting for as long as 

6 hours to remove fine-grained material from the 

sump, screen, and gravel pack.

Water-Level Measurements

A large amount of ground-water-level data were 

collected during this study. As part of an initial 

reconnaissance effort, the 106 monitoring wells 

sampled in 1981 and 1983 (Buxton and Shernoff, 

1995) were visited in 1992, and a water-level 

measurement was made, if possible. The 

hydrogeologic units in which these wells are screened 

are as follows: upper glacial aquifer, 64 wells; JamecoMagothy aquifer, 31 wells; Raritan clay, 1 well; and 

Lloyd aquifer, 10 wells. A water-level-monitoring 

network was designed from a subset of these sampled 

wells and other available wells. Water-level 

measurements were obtained by the “wetted-tape” 

method (U.S. Geological Survey, 1980). Water level 

measurements were collected monthly beginning in 

1992, but the frequency of measurements was 

decreased to quarterly in 1994. Water-table maps and 

potentiometric heads are depicted in figures 3A-I, 4, 

and 5, and are discussed further on. In addition to 

water-level data collected specifically for this study, 

the USGS has maintained a monitoring-well network 

in Kings and Queens Counties at which water levels 

have been measured monthly since as early as 1934. 

The number of water-level measurements obtained 

from all wells in Kings and Queens during 1910-95, 

by decade, are presented in Monti (1997).

Ground-Water Sampling

The water-quality data collected during this study 

form the most comprehensive data set for the study 

area. Methods of sample collection and qualityassurance techniques used are described in Cartwright 

and others (1998). Water samples were collected from 

monitoring wells with a pump or bailer; samples from 

industrial-supply or other private wells typically were 

obtained from a spigot. Chemical analyses of samples 

collected by the USGS were performed at the USGS 

laboratory in Arvada, Colo. Water-quality data for 

public-supply wells, which were not sampled by the 

USGS, are from the Jamaica Water Supply Company 

(JWS) data base. All JWS water-quality data presented 

in this report are from raw well water, which was 

collected prior to any treatment or distribution. All 

wells in the ground-water sampling network and the 

periods of sampling are summarized in table 3; well 

locations and aquifer designation are depicted in 

fig. 6A-I. Data on chloride, nitrate, and volatile 

organic compound concentrations are discussed 

further on. 

Geophysical Logging

Five borehole-logging techniques were used in 

this study—natural gamma (G), spontaneous potential 

(SP), single-point resistance (SPR), normal resistivity 

(R), and electromagnetic induction conductivity (EM). 

Eleven wells were logged with at least one, and as 

many as five, of these techniques (three wells were 

logged with all five techniques, five were logged with 

only with G and EM probes, and three were logged 

only with the G probe). All SP, SPR, and R logs were 

obtained in an open borehole; the G logs were 

obtained through open boreholes or PVC casing, and 

all EM logs were obtained through PVC casing.

HISTORY AND HYDROLOGIC EFFECTS 

OF GROUND-WATER DEVELOPMENT

The amount, distribution, movement, and quality 

of surface water and ground water in Kings and 

Queens Counties have been altered by human 

activities since the early 1800’s. The history of 

ground-water development in Kings and Queens 

Counties from 1900 through 1983 is presented in 

Buxton and Shernoff (1995), which describes the 

development of the ground-water supply, including 

withdrawals by aquifer and location in each of the two 

counties; it also describes the water-level changes that 

have resulted from the pumping practices, and the 

changes in chloride and nitrate concentrations through 

time. The following section (paraphrased from Buxton 
10 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Table 3. Water samples collected from the monitoring-well network in Kings, Queens, and western 

Nassau Counties, N.Y., 1983-96

[Well locations are shown in figure 5A-I. Prefix K, Kings County; Q, Queens County; N, Nassau County. I, industrial well; 

M, monitoring well; D, diffusion well; NA, not available. U. glacial, upper glacial aquifer; Jameco, Jameco aquifer; 

Magothy, Magothy aquifer; Raritan, Raritan clay; Lloyd, Lloyd aquifer. Dashes indicate well status unknown]

Well status on date of sample collection

Well

number

Well

use

Hydrogeologic

unit

February through

April 1981

June through

October 1983

August 1992 through

January 1993

July through

September 19951 March throughJuly 1996

K20 I U. glacial sampled -- -- -- --

K41 I U. glacial sampled -- -- -- --

K307 NA U. glacial sampled -- -- -- --

K922 I Jameco -- sampled -- -- --

K1189 I Jameco sampled sampled -- -- --

K1194 M U. glacial sampled -- -- -- --

K1673 I U. glacial sampled sampled sampled sampled

K1678 I U. glacial sampled sampled sampled sampled

K1681 I U. glacial sampled -- -- -- --

K1689 I U. glacial sampled sampled sampled sampled

K2040 I U. glacial sampled sampled -- inaccessible

K2135 NA U. glacial sampled -- -- -- --

K2284 I U. glacial sampled -- -- -- --

K2303 I U. glacial sampled -- -- -- --

K2407 I U. glacial sampled sampled sampled sampled

K2412 I U. glacial sampled sampled sampled sampled

K2482 I U. glacial sampled sampled sampled sampled

K2510 I Jameco sampled sampled sampled sampled

K2511 I Jameco -- sampled -- sampled

K2514 NA U. glacial sampled -- -- -- --

K2582 I Jameco -- sampled sampled sampled

K2591 I U. glacial sampled sampled -- destroyed

K2594 NA U. glacial sampled -- -- -- --

K2598 I U. glacial -- sampled sampled sampled

K2610 I U. glacial sampled sampled sampled sampled

K2622 I U. glacial sampled sampled sampled sampled

K2859 I Lloyd sampled sampled sampled obstructed 

K3130 I Jameco -- sampled -- obstructed

K3132 I Jameco -- sampled -- inoperable pump

K3133 I Jameco sampled sampled sampled sampled

K3151 I U. glacial -- sampled sampled sampled

K3214 I U. glacial -- sampled sampled sampled

K3215 I U. glacial sampled -- -- -- --

K3216 I U. glacial -- sampled sampled --

K3217 I U. glacial sampled -- -- -- --

K3218 I U. glacial sampled sampled sampled sampled

K3220 NA Jameco sampled -- -- -- --

K3242 I U. glacial -- sampled sampled sampled

K3243 NA U. glacial sampled -- -- -- --

K3245 M U. glacial sampled sampled sampled obstructed

K3246 M U. glacial sampled sampled sampled sampled

K3247 M U. glacial sampled sampled -- low yield

K3248 M U. glacial sampled sampled sampled sampled

K3249 M U. glacial sampled sampled sampled obstructed

K3250 M U. glacial sampled sampled sampled sampled

K3251 M U. glacial sampled sampled sampled sampled

K3252 M U. glacial sampled sampled sampled sampled

K3253 M U. glacial -- sampled sampled sampled

K3254 M U. glacial sampled sampled sampled sampled

K3255 M U. glacial sampled sampled sampled low yield
History and Hydrologic Effects of Ground-Water Development 11

Table 3. Water samples collected from the monitoring-well network in Kings, Queens, and western 

Nassau Counties, N.Y., 1983-96--continued

Well status on date of sample collection

Well

number

Well

use

Hydrogeologic

unit

February through

April 1981

June through

October 1983

August 1992 through

January 1993

July through

September 19951 March throughJuly 1996

K3256 M U. glacial sampled sampled sampled poor yield

K3257 M U. glacial sampled sampled sampled poor yield

K3260 M U. glacial sampled sampled -- low yield

K3267 I U. glacial sampled sampled sampled sampled

K3271 M U. glacial -- sampled sampled inaccessible

K3272 M U. glacial -- sampled destroyed destroyed destroyed

K3273 M U. glacial -- sampled sampled dry

K3275 M U. glacial -- sampled sampled sampled

K3276 M U. glacial -- sampled sampled sampled

K3405 M Jameco nonexistent nonexistent nonexistent sampled sampled

K3406 M U. glacial nonexistent nonexistent nonexistent sampled sampled

K3407 M Jameco nonexistent nonexistent nonexistent sampled sampled

K3410 M Lloyd nonexistent nonexistent nonexistent sampled sampled

K3414 M Magothy nonexistent nonexistent nonexistent sampled sampled

K3424 M U. glacial nonexistent nonexistent nonexistent sampled dry

K3425 M U. glacial nonexistent nonexistent nonexistent sampled sampled

K3426 M Lloyd nonexistent nonexistent nonexistent sampled sampled

K3430 M U. glacial nonexistent nonexistent nonexistent sampled

K3431 M Magothy nonexistent nonexistent nonexistent sampled

KA2 I U. glacial sampled -- -- -- --

KB2 I U. glacial sampled -- -- -- --

Q 273 M Lloyd sampled sampled sampled --

Q 277 M Magothy -- sampled sampled sampled

Q 283 M Lloyd sampled -- -- -- --

Q 287 M Lloyd -- sampled sampled sampled

Q 470 M Lloyd sampled sampled sampled sampled

Q 471 M Magothy sampled sampled sampled sampled

Q1071 M Lloyd sampled sampled sampled sampled

Q1187 M Jameco -- sampled sampled inaccessible

Q1189 M U. glacial sampled sampled sampled sampled

Q1237 M Jameco -- sampled sampled sampled

Q1241 I Lloyd sampled sampled sampled denied access

Q1373 M Lloyd -- sampled sampled sampled

Q1472 I Magothy -- sampled sampled sampled

Q1506 I U. glacial -- sampled -- destroyed

Q1605 I U. glacial sampled sampled sampled denied access

Q1663 I U. glacial sampled sampled sampled sampled

Q1914 I Magothy -- sampled sampled sampled

Q1930 I U. glacial sampled sampled sampled sampled

Q2289 I U. glacial -- sampled -- denied access

Q2324 M U. glacial sampled sampled sampled sampled

Q2384 I U. glacial -- sampled -- denied access

Q2407 I U. glacial -- sampled sampled sampled

Q2418 M U. glacial sampled sampled sampled sampled

Q2419 M Lloyd sampled sampled sampled sampled

Q2420 M Lloyd sampled sampled sampled sampled

Q2426 I Magothy -- sampled pump removed pump removed pump removed

Q2656 I U. glacial sampled sampled sampled sampled

Q2791 I U. glacial sampled sampled sampled sampled

Q2814 I U. glacial -- sampled sampled sampled

Q2964 NA U. glacial sampled -- -- -- --

Q2965 NA U. glacial sampled -- -- -- --

Q2978 I U. glacial sampled sampled sampled sampled

Q2993 M U. glacial sampled sampled -- destroyed

Q2994 M U. glacial -- sampled sampled sampled

Q2995 M U. glacial sampled sampled sampled sampled
12 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Q3003 I Magothy -- sampled sampled sampled

Q3015 I Magothy -- sampled pump removed pump removed pump removed

Q3036 I Lloyd sampled sampled sampled sampled

Q3109 M Magothy -- sampled sampled sampled

Q3110 M Jameco -- sampled sampled sampled

Q3112 M Jameco -- sampled sampled sampled

Q3114 M U. glacial -- sampled sampled sampled

Q3115 M U. glacial -- sampled sampled sampled

Q3117 M U. glacial sampled sampled sampled sampled

Q3119 M U. glacial sampled sampled sampled sampled

Q3120 M U. glacial sampled -- -- -- --

Q3121 M U. glacial sampled sampled sampled poor yield

Q3123 M U. glacial sampled sampled -- destroyed

Q3134 I U. glacial -- sampled sampled sampled

Q3150 M Jameco -- sampled -- bent casing

Q3587 M U. glacial nonexistent nonexistent nonexistent sampled sampled

Q3589 M Magothy nonexistent nonexistent nonexistent sampled sampled

Q3593 M Lloyd nonexistent nonexistent nonexistent sampled sampled

Q3604 M U. glacial nonexistent nonexistent nonexistent sampled sampled

Q3627 M Lloyd nonexistent nonexistent nonexistent sampled sampled

Q3628 M Lloyd nonexistent nonexistent nonexistent sampled sampled

Q3629 M U. glacial nonexistent nonexistent nonexistent sampled sampled

Q3644 M U. glacial nonexistent nonexistent nonexistent sampled sampled

Q3646 M U. glacial nonexistent nonexistent nonexistent sampled sampled

Q3648 M U. glacial nonexistent nonexistent nonexistent sampled

Q3649 M U. glacial nonexistent nonexistent nonexistent sampled sampled

Q3650 M U. glacial nonexistent nonexistent nonexistent sampled

Q3651 M U. glacial nonexistent nonexistent nonexistent sampled sampled

Q3652 M U. glacial nonexistent nonexistent nonexistent sampled

Q3658 M U. glacial nonexistent nonexistent nonexistent sampled

Q3659 M U. glacial nonexistent nonexistent nonexistent sampled sampled

Q3660 M U. glacial nonexistent nonexistent nonexistent sampled sampled

Q3661 M U. glacial nonexistent nonexistent nonexistent sampled

Q3662 M -- nonexistent nonexistent nonexistent obstructed

N1102 M U. glacial sampled -- -- -- --

N1104 M U. glacial sampled -- -- -- --

N1105 M U. glacial sampled -- -- -- --

N1429 M U. glacial sampled sampled obstructed

N1622 M U. glacial sampled -- -- -- destroyed

N1627 M U. glacial sampled sampled sampled sampled

N3864 M Magothy -- sampled sampled sampled

N3867 M Magothy -- sampled sampled sampled

N3932 M Jameco -- sampled sampled sampled

N4026 M Jameco -- sampled sampled sampled

N4062 M Jameco -- sampled sampled sampled

N4213 M Jameco -- sampled sampled sampled

N6581 M Magothy -- sampled sampled sampled

N6701 M Raritan -- sampled sampled sampled

N6703 M Magothy -- sampled sampled sampled

N6707 M Magothy -- sampled sampled sampled

N6792 M U. glacial -- sampled sampled sampled

N7161 M Magothy -- sampled sampled sampled

N8373 D U. glacial sampled -- -- -- --

N8877 M U. glacial -- sampled sampled sampled 1 Only new wells were sampled during this period; blanks indicate non-targeted well

2

 New York State Department of Environmental Conservation well-identification number unavailable

Well status on date of sample collection

Well

number

Well

use

Hydrogeologic

unit

February through

April 1981

June through

October 1983

August 1992 through

January 1993

July through

September 19951 March throughJuly 1996

Table 3. Water samples collected from the monitoring-well network in Kings, Queens, and western Nassau 

Counties, N.Y., 1983-96--continued
Recent (1992-97) Hydrologic Conditions 13

and Shernoff, 1995) discusses the history of groundwater development; this information and more recent 

data are summarized in table 4.

Water-Supply Practices and their Effects on 

the Hydrologic System

Early residents of Kings and western Queens 

Counties obtained water from shallow wells and 

streams, and returned most of it to the aquifer through 

septic systems. This practice had a negligible effect on 

the ground-water system initially, but as the 

population grew, the demand for public and industrial 

supply increased and required more wells and 

increased pumpage. By the mid-1800’s, storm sewers 

and sanitary sewers had been installed in Kings 

County. These systems channeled wastewater to 

coastal water bodies to minimize the amounts of 

contaminants reaching the ground-water system, but 

also sharply diminished recharge. By the turn of the 

20th century, rapid population growth and 

development in Kings and Queens Counties was 

demanding even greater ground-water withdrawals, 

while the increasing amounts of impervious-surface 

area (streets and parking lots) and sewering further 

decreased aquifer recharge. The first New York City 

tunnel to bring water from upstate reservoirs to Kings 

and Queens Counties was completed in 1917. This 

importation of water resulted in a large decrease in 

ground-water withdrawals, but the continued 

population growth soon prompted increased groundwater withdrawals once again. By the 1930’s, large 

water-level declines had developed in the water table 

and in deeper aquifers; these declines in northwestern 

Kings County caused saltwater encroachment. In 

1933, the New York State Conservation Law required 

that ground-water withdrawals greater than 100,000 

gal/d (0.1 Mgal/d) be returned to the aquifer. This law, 

and the increasing use of electric refrigeration, which 

reduced the amounts of water pumped for ice-making, 

resulted in a decreased net loss from the aquifers 

through industrial ground-water pumping. In 1936, the 

second water tunnel to Kings and Queens Counties 

was completed, but this additional supply was 

probably used in newly developed areas, and no 

noticeable decrease in ground-water withdrawals was 

observed. As the water table and heads in the deep 

aquifers continued to decline, saltwater intrusion 

increased until it forced the cessation of all publicsupply withdrawals in Kings County by 1947. This 

cessation allowed the system to recover, and by 1950, 

the water table in Kings County had risen about 20 ft. 

The water-supply deficit caused by the cessation of 

pumping in Kings County was made up by additional 

supplies from wellfields in Queens County. 

Eventually, many wells in Queens, also became 

contaminated with salty ground water. As a result, new 

wellfields were developed farther inland and to the 

east until 1974, when all public-supply pumping in 

Queens County ceased, except for the former JWS in 

southern Queens County (now owned and operated by 

NYCDEP). 

Historical Ground-Water Levels

The water-table configuration in Kings and 

Queens Counties from 1903 to 1983 is depicted in a 

series of water-table maps in Buxton and Shernoff 

(1995). Those maps are reproduced here (figs. 3A-3I) 

for comparison with recent (1992-97) conditions. The 

chronology of events and effects regarding historical 

water-table changes are summarized in table 4. The 

relation between ground-water development, use, and 

disposal, and the effects these practices have had on 

ground-water levels, are discussed in the “GroundWater Levels” section. 

RECENT (1992-97) HYDROLOGIC 

CONDITIONS

The recent (1992-97) ground-water system is 

relatively static in relation to conditions earlier in the 

20th century, mainly because withdrawals for public 

supply have decreased to historic lows and are 

confined to a small area of southeastern Queens 

County. Much of the system now is close to 

equilibrium conditions after decades of recovery, or is 

undergoing only slight adjustments in response to 

localized withdrawals for public or industrial supply 

(including dewatering operations). This relative 

stability does not imply an absence of stress on the 

system, but rather a balance of ground-water inflow 

and outflow, as described in the following sections. 

Ground-water quality in the study area varies 

areally and with depth. Many point sources of 

contamination at land surface continue to affect water 

quality, and saltwater intrusion remains a concern in 

some areas, especially where water-level gradients 

were reversed twice during the 20th century. Ground-
14 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Table 4. History and hydrologic effects of ground-water use in Kings and Queens Counties, N.Y., 1800’s through 1996[Mgal/d, million gallons per day; NYC, New York City; JWS, Jamaica Water Supply Company. Data from Buxton and Shernoff, 1995, unless cited oth

Period Event or trend

Estimated ground-water withdrawals, 

in Mgal/d

Ef

Public supply Industrial supply

Kings

County

Queens

County

Kings

County

Queens

County

Early 

1800’s

Rapid population growth in Kings and western Queens Counties, and 

development of shallow ground-water use. Most water was returned to the ground through septic systems.

Unknown Unknown Unknown Unknown Negligible effect on water

shallow flow paths. Wasshallow ground-water sy

Mid

1800’s

Continued population growth and attendant development of roads 

and other impervious surfaces. Continued development of groundwater use. In Kings County, installation of storm and sanitary sewers that discharged wastewater to the sea. 

Unknown Unknown Unknown Unknown Water table probably show

1904 Withdrawals for public- and industrial-supply continued to increase. 

Subways were constructed in the early 1900’s as water table was declining.

14 28 14 Few Water table probably show

Salt-water encroachment i

Bay (Spear, 1912). Nitraaquifer in Kings County 

1910 Withdrawals continued to increase; highest public-supply withdrawals in Kings County to date. 33 65 21 Few Water table probably show

1917 First NYC Water Tunnel completed; replaced significant amount of 

ground water pumped for public supply by NYC Department of Water Supply, Gas and Electricity. Private water suppliers continued withdrawals, and industrial withdrawals increased. Until this time, most ground water came from upper Glacial and Jameco aquifers.

12 23 42 Probably 

between 

10 and 20

Despite reduction in publi

NYC Department of WaElectricity, water table pbecause withdrawals for private water suppliers h

1927 Withdrawals continued to increase; highest industrial-supply 

withdrawals were in Kings County.

22 35 52 Probably 

about 20

Water table probably showSaltwater intrusion into up

became more widesprea

1928-

33

Pumping shifted from upper glacial to Jameco (and to a lesser extent, 

Lloyd) aquifers in Kings County, and withdrawals from all deep aquifers increased in Queens County. Maximum amount of public and industrial supply in Kings County totaled 75 Mgal/d in 1929. By 1933, as much as 16 Mgal/d was pumped from confined aquifers (mostly from Jameco), and nearly all withdrawals were ultimately discharged to sewers (Perlmutter and Soren, 1962).

Averaged

about 25 

Averaged 

about 49 

Averaged 

about 46 

Probably 

averaged 

about 17 

Saltwater encroachment in

required a shift to pumpWater levels in confined response to excessive pucoefficient characteristic of depression noted in Qand Soren, 1962).

1930’s Decline in industrial withdrawals in response to adoption of New 

York State Water Conservation Law requiring that pumpage in 

excess of 0.1 Mgal/d be reinjected to source aquifer, and widespread use of electric refrigeration resulting in decreased pumpage for making ice.

Averaged 

about 25 

Averaged 

about 49

Averaged 

about 38 

Probably 

averaged 

about 17

Severe declines in water le

confined aquifers. Many and flow in remaining stencroachment progressesupply withdrawals allo
15

Table 4. History and hydrologic effects of ground-water use in Kings and Queens Counties, N.Y., 1800’s through 1996--con

Period Event or trend

Estimated ground-water withdrawals, 

in Mgal/d

E

Public supply Industrial supply

Kings

County

Queens

County

Kings

County

Queens

County

1936 Second NYC Water Tunnel completed; no reduction in ground-water 

withdrawals evident. Imported water probably used to convert new areas to public supply.

An estimated 49 billion gallons of freshwater had been removed from 

the shallow aquifer in Kings from 1903 through 1936 (Perlmutter and Soren, 1962).

27 44 37 Probably 

about 18 

Water levels continued to 

encroachment progresse35 feet below sea level dCounty, where water lev1903 (Veatch and othersKings County was below depression extended into (Suter, 1937).

1943 Continued decline in industrial-supply withdrawals since about 1930. 25 36 25 Probably 

about 15 

Water table showed some 

western Queens County encroachment continued 

1947 Withdrawals for public supply in Flatbush (Kings County) were 

stopped, mostly in response to saltwater intrusion. Withdrawals increased in Queens County to compensate for shutdown of wellfields in Kings County.

0 47 25 Probably

about 15

Widespread chloride cont

aquifer in Kings Countystarted recovery in KingFlatbush required dewatper minute. Increased wcaused water-level declicontamination of publicaquifer in Flatbush franc

1951 Industrial-supply withdrawals decreased in Kings and Queens 

Counties.

0 36 16 10 Cone of depression in nor

smaller and rose to 25 flevels in southern Kings level (Lusczynski and Jocentral Kings County hafeet since 1947 and storincreased by about 20 b1952). Basement and suwest and northwest of E(Soren, 1976).

1955-

76

Shift in pumping from upper glacial aquifer to Magothy aquifer (and 

to a lesser degree, Lloyd aquifer) in Queens County. Overall increase in public supply withdrawals in Queens County. Maximum withdrawal for public supply in Queens County was 70 Mgal/d in 1970.

0 45 to 61 About 10 About 8 to 

about 4 

Water-table recovery cont

Basement and subway flEast New York (Kings Ctions increased in publicCounty.

Recent (1992-97) Hydrologic Conditions
16 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997 1961 Public-supply withdrawals in Queens County increased; all other withdrawals remained steady. Wells with high chloride concentra- tions in Queens County were abandoned and new wells were installed farther inland and eastward. From 1903 to 1961, about 51 

billion gallons of fresh-water were removed from the water-table aquifer in Queens County (Perlmutter and Soren, 1962).

0 54 About 10 About 5 Water table throughout Ki

level, recovering by as mextreme northern part; cdeclining. Subway-tunnincreased to 1,000 gallocone of depression (abolevels) developed in sou(Woodhaven franchise atable throughout southeand Soren, 1962).

1974 Withdrawals for public supply in Woodhaven franchise area of 

Queens County stopped because of saltwater intrusion; withdrawals by JWS continued at about 57 Mgal/d.

0 57 <10 About 4 Further recovery of water 

table configuration now of depression in Queens Woodhaven area toward part of cone was 35 feet Potentiometric surfaces but data on historical lev

1983 Continued withdrawals by JWS from southeastern Queens County; 

mostly from Jameco-Magothy aquifer, with lesser amounts from upper glacial and Lloyd aquifers. An additional 6 Mgal/d was pumped from wells in Kings County, and about 2 Mgal/d from wells in Queens County for dewatering operations.

0 57 6.6 2.3 Since 1974, water-table flu

Kings County indicate a equilibrium. Water levelsouthwestern Queens Cfeet and more than 1 fooAlthough data are sparsQueens County apparenthose in southeastern QuFranchise area) dropped extreme southwestern Ndeclines of as much as 4 

1991 Continued reductions in withdrawals from Queens County, partly 

through successful implementation of NYCDEP’s water-conservation plan; public-supply withdrawals are from former JWS wells in Jamaica. 

Repairs to water mains result in decreased leakage into ground-water 

reservoir. Increased dewatering in Kings County; industrial-supply withdrawals in Kings County are estimates and include dewatering operations (Misut and Monti, 1999).

0 24 22 15 Water-table recovery in Ja

in response to decreased supply.

Water-table declines in par

increases in industrial-sdrawals.

1996 Continued reductions in ground-water withdrawals from Queens 

County, as NYCDEP takes over JWS; public-supply withdrawals are from former JWS wells in Jamaica (Misut and Monti, 1999).

Increased dewatering withdrawals in southeastern Queens County.

0 14 22 15 Continued water-table rec

Queens County results fpublic supply.

Period Event or trend

Estimated ground-water withdrawals, 

in Mgal/d

E

Public supply Industrial supply

Kings

County

Queens

County

Kings

County

Queens

County

Table 4. History and hydrologic effects of ground-water use in Kings and Queens Counties, N.Y., 1800’s through 1996--con
Recent (1992-97) Hydrologic Conditions 17

water quality in the study area varies areally and with 

depth. Many point sources of contamination at land 

surface continue to affect water quality, and saltwater 

intrusion remains a concern in some areas, especially 

where water-level gradients were reversed twice 

during the 20th century.

Ground-Water Withdrawals

Ground-water withdrawals can be classified as 

consumptive—no water is returned to the groundwater reservoir—or nonconsumptive—water is 

returned to the ground-water system through 

reinjection, wastewater-disposal systems, or leakage 

from the water-distribution system. Water suppliers 

report ground-water withdrawals as the total amount 

of water pumped or supplied to customers, whether or 

not it is ultimately returned to the ground-water 

system. The difference between the two totals 

represents the amount that is reinjected into the ground 

after use plus the amount that is returned to the system 

through leaking distribution mains. The net effect is 

that withdrawals reported by water suppliers are 

greater than the amount that is permanently removed 

from the system. Available records of ground-water 

withdrawals compiled in this study from various water 

suppliers represent estimates of the total amounts 

pumped. The principal types of withdrawals, and their 

estimated amounts, are as follows.

Public Supply

Public-supply withdrawals were greatest before 

the 1930’s and decreased until the early 1990’s, when 

the only public-supply pumping in Kings and Queens 

Counties was 22 Mgal/d from the former JWS 

wellfields in Queens County (Chu and others, 1997). 

Most of this amount is considered consumptive. By 

1995, withdrawals had decreased to about 17 Mgal/d 

and, when the NYCDEP purchased the JWS in 1996, 

withdrawals were cut further to about 14 Mgal/d; most 

of this also is considered consumptive withdrawals 

(John Dydland, New York City Department of 

Environmental Protection, written commun., 1996). 

Plans to increase withdrawals from the Jamaica 

wellfields to help alleviate underground flooding are in 

progress (John Dydland, New York City Department 

of Environmental Protection, oral commun., 1996).

Industrial Supply

Industrial-supply withdrawals are more difficult 

to estimate than public-supply withdrawals, and the 

only source of this information is the NYSDEC. 

Establishments planning to install wells from which 

water will be withdrawn at rates exceeding 40 gal/min 

(0.058 Mgal/d) are required to obtain a permit from 

the NYSDEC, and those pumping more than 

70 gal/min (0.1 Mgal/d) must return the used water 

into the source aquifer. If all water pumped at a rate 

greater than 70 gal/min (0.1 Mgal/d) is reinjected to 

the source aquifer, then the amount of consumptive 

use for industrial supply is equal to the reported 

amounts pumped at rates between 40 and 70 gal/min, 

plus the amounts that are pumped at rates less than 

40 gal/min (which are not required to be reported); this 

estimate assumes no return flow of water pumped at 

rates less than 70 gal/min for industrial supply. Misut 

and Monti (1999) estimated industrial-supply 

withdrawals (derived from pump capacities filed with 

NYSDEC) to be 22 Mgal/d for Kings County and 

15 Mgal/d for Queens County. These estimates, which 

are calculated from individual pump capacities and 

assume a pumping period of 8 hours per day, probably 

are high because actual pumping rates generally are 

less than the maximum capacity rating of each pump.

Dewatering

The recovery of ground-water levels in response 

to decreased withdrawals has caused flooding of 

underground structures such as basements and subway 

tunnels that were constructed in some coastal areas 

during the early development of Kings and Queens 

Counties. Dewatering of these structures requires 

continuous pumping. The pumped water is directed to 

the combined sanitary and stormwater sewer system, 

which ultimately discharges to nearby saltwater bodies 

and thereby removes the water from the ground-water 

system; thus, dewatering operations are considered a 

consumptive use. Dewatering accounts for at least 30 

percent of the estimated 37 Mgal/d pumped for 

industrial use in Kings and western Queens Counties. 

The Metropolitan Transit Authority (MTA) alone 

withdraws more than 10 Mgal/d from subway tunnels 

in Kings County (Misut and Monti, 1999).
18 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Ground-Water Inputs

Most ground-water systems are recharged by 

precipitation that infiltrates the soil. In the highly 

developed area of Kings and Queens Counties, 

however, recharge from precipitation is impeded by 

impervious surfaces, and recharge from leaky sewer 

and supply lines is significant by comparison.

Precipitation

Precipitation supplies virtually all recharge in 

central and eastern Long Island. Recharge in 

undeveloped areas of Long Island is estimated to equal 

about 50 percent of mean annual precipitation, but 

recharge from precipitation in the highly urbanized 

and industrialized areas of Kings and Queens Counties 

is far less because the large amount of impervious 

surfaces such as streets and parking lots impede 

infiltration. In 1983, Buxton and Shernoff (1995) 

estimated recharge from precipitation to equal only 

about 15 percent of precipitation (24 Mgal/d) in Kings 

County, and about 35 percent of precipitation 

(83 Mgal/d) in Queens County. These 1983 values are 

considered accurate for present conditions because the 

amount of impervious surfaces has not changed 

appreciably since then.

Leaky Sewer Lines and Water Mains

Wastewater in Kings and Queens Counties 

initially was returned to the ground through septic 

systems before sewers were installed in the 19th 

century. Septic systems provided continual recharge of 

the ground-water system, but soon caused widespread 

nitrate contamination of the upper glacial aquifer. The 

first combined sanitary and storm sewers on Long 

Island were installed in Kings County by the mid1800’s, and Queens County had an extensive sewer 

network by the turn of the 20th century. Although 

sewers prevented most surface-derived contamination 

from reaching the water table, it also prevented large 

volumes of water from recharging the ground-water 

system and, thereby, resulted in lowering the water 

table. Leakage from sewer connections and broken 

lines initially was small, and probably was 

insignificant in relation to the large public-supply 

withdrawals. The amount of leakage from combined 

sanitary and storm sewers has probably increased, as 

the lines have aged, however. Leakage into the ground 

water from leaky sewer lines and water-supply mains 

in 1983, as calculated from the number of miles of 

mains and the number of connections, multiplied by a 

leakage factor, is estimated to have been about 

30 Mgal/d in Kings County and 40 Mgal/d in Queens 

County (Buxton and Shernoff, 1995). Ground-water 

leakage from sewer and supply lines has become an 

increasingly large component of the ground-water 

budget as public-supply withdrawals decline and sewer 

and supply lines age. 

Recent water-conservation efforts by New York 

City, such as shutting off running water in vacant 

buildings, repairing leaks, reducing water-supply 

waste, installing water meters in areas that had flat-rate 

billing, and educating consumers in water 

conservation, probably have decreased the amount of 

water returning to the ground-water system through 

sewers and water-supply main leakage. Also, the 

infiltration of ground water from the recovering water 

table into sewer lines probably occurs more widely 

now than when the water table was depressed. The 

potential for greater leakage from aging sewer and 

supply lines is countered by leakage decreases 

resulting from water-conservation efforts and the 

rising water table. Therefore, with a lack of additional 

data, the estimated ground-water input from watersupply and sewer lines is probably similar to the 1983 

estimates (Buxton and Shernoff, 1995).

Ground-Water Levels

The water-table configurations in Kings and 

Queens Counties in 1903, 1936, 1943, 1951, 1961, 

1974, 1981, 1983, and 1997 are depicted in figures 

3A-3I, respectively. Water levels in the JamecoMagothy aquifer in 1983 and 1996 are depicted in 

figure 4; water levels in these years in the Lloyd 

aquifer are depicted in figure 5. Well-design and 

water-level data from wells installed before 1983 are 

presented in table 8 of Buxton and Shernoff (1995), 

and well-completion data from new wells (since 1992) 

are presented in table 2 of this report. The following 

sections describe present (1997) ground-water levels 

in the major aquifers in Kings, Queens, and western 

Nassau Counties, and discuss them in relation to those 

of 1983 in light of the sharply reduced public-supply 

withdrawals in Queens in 1974.

Upper Glacial Aquifer

Kings County.—The cessation of public-supply 

withdrawals in Kings County in 1947 caused water 
Recent (1992-97) Hydrologic Conditions 19

40°45'

74°00' 73°45'

Base modified from U.S. Geological Survey, 1:100,000;

Hydrography and cultural features modified to reflect

the period from 1903 through 1936

Atlantic Ocean

East

River

Flushing Bay

Jamaica Bay

Flushing

Creek

Little Neck

Bay

KINGS

COUNTY

QUEENS

COUNTY

NASSAU

COUNTY

5

5

5

5

10

10

10

10

20

20

20

20

30

30

30

40

50

40

40

40

50

EXPLANATION

5 WATER-TABLE CONTOUR – Shows altitude of water table.

Contour interval 5 and 10 feet. Datum is sea level.

0 1 2 3 4 5 MILES

0 1 2 3 4 5 KILOMETERS

levels to begin rising. By 1974, the water-table 

configuration in Kings County (fig. 3F) was similar to 

that of 1903 (fig. 3A). This condition, and the 

relatively small (about 1-ft) water-level fluctuations 

observed since 1974, indicate that the system is now 

close to equilibrium. By 1991, small localized waterlevel declines were observed; these were caused by 

dewatering in response to ground-water flooding and 

had a negligible effect on the overall recovery of water 

levels. The 1997 water-table map (fig. 3I) indicates 

water levels throughout Kings County to be mostly 

from 0 to 10 ft above sea level.

Queens and western Nassau Counties.—Since 

1974, water levels in Queens County have risen above 

sea level in all but one area in the southern part of the 

county that contains the JWS wellfields. In 1974, 

water levels in this area were between 0 and 10 ft 

below sea level (fig. 3F), but by 1983, continued 

recovery had divided this depression into two smaller 

depressions—one less than 1 ft below sea level in 

south-central Queens County, and one about 10 ft 

below sea level in southeastern Queens County 

(fig. 3H). The latter depression is due to past pumping 

by the JWS for their Woodhaven operations, and the 

former depression is the result of continued (but 

decreased) withdrawals by the JWS. Water levels 

about 3 mi east-northeast of this depression (in 

western Nassau County) are as much as 40 ft higher 

FIGURE 3A. Water-table configuration in Kings, Queens, and western Nassau Counties, N.Y., in 

1903. (From Buxton and Shernoff, 1995, fig. 3.)
20 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

40°45'

74°00' 73°45'

Base modified from U.S. Geological Survey, 1:100,000;

Hydrography and cultural features modified to reflect

the period from 1903 through 1936

Atlantic Ocean

East

River

Flushing Bay

Jamaica Bay

Flushing

Creek

Little Neck

Bay

KINGS

COUNTY

QUEENS

COUNTY

NASSAU

COUNTY

0 1 2 3 4 5 MILES

0 1 2 3 4 5 KILOMETERS

10

10

10

20

20

30

40

0

0

-10

-20

-30

EXPLANATION

0 WATER-TABLE CONTOUR – Shows altitude of water table. Contour

interval 10 feet. Datum is sea level. Hachures indicate depression. 

and provide a steep southwestward gradient. Both 

depressions in Queens County had disappeared by 

1997, as indicated by the most recent water-table map 

(Monti and Chu, 1997), which shows little, if any, 

indication of residual effects of pumping (fig. 3I). 

Currently (1997), water levels are about 20 ft above 

sea level in areas where they were 10 ft below sea level 

in 1983. This recovery is the result of a 75-percent 

reduction in ground-water withdrawals for public 

supply in Jamaica, from about 57 Mgal/d in 1983 to 

about 14 Mgal/d in 1996. Water levels in western 

Nassau County also show a recovery, especially in 

areas closest to the former depression in Queens 

County. Especially notable is the shift in direction of 

ground-water flow, which was to the southwest 

(toward Queens County) in 1983, and to the southsouthwest (closer to the direction of regional 

southward flow) in 1997.

Jameco-Magothy Aquifer

The 1983 potentiometric surface of the JamecoMagothy aquifer in Kings County, as indicated by data 

from two wells (Buxton and Shernoff, 1995, pl. 5), 

FIGURE 3B. Water-table configuration in Kings, Queens, and western Nassau Counties, N.Y., 

in 1936. (From Buxton and Shernoff, 1995, fig. 6A.) 
Recent (1992-97) Hydrologic Conditions 21

Base modified from U.S. Geological Survey, 1:100,000;

Hydrography and cultural features modified to reflect

the period from 1943 through 1951

Atlantic Ocean

East

River

Flushing Bay

Flushing Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

0 1 2 3 4 5 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

0 WATER-TABLE CONTOUR – Shows altitude of water table. Contour

interval 10 feet. Datum is sea level. Hachures indicate depression. 

10

50

40

30

20

0

-10

-20

-30

0

generally was less than 10 ft above sea level. The 1983 

potentiometric surface in Queens County, based on 

data from 18 wells, indicates a large depression 

beneath the southern half of the county’s mainland, 

where water levels range from 0 to about 10 ft below 

sea level. This depression is the result of public-supply 

withdrawals from 22 wells at a combined rate of about 

31 Mgal/d during the March-through-April 1983 

measurement period (Buxton and Shernoff, 1995). 

Water levels in adjacent western Nassau County 

indicate a potentiometric surface that dips steeply to 

the southwest toward this depression—from 30 ft to 

less than 5 ft above sea level in about 2.5 mi. The few 

water-level measurements made in northern Queens 

County in 1983 range from 0 to about 13 ft above sea 

level, and those along the coast south of the large 

depression in Queens County range from 0 to 4 ft 

above sea level. Water levels in southern Nassau 

County also range from 0 to 4 ft above sea level.

Public-supply withdrawals from the JamecoMagothy aquifer in Queens County in 1995 averaged 

11.7 Mgal/d. This value is calculated from the total 

yearly amount divided by 365 and, therefore, probably 

should be higher than the 1983 daily averages 

(31 Mgal/d) calculated only for March through April, 

when pumping rates typically are lower than in other 

seasons. Thus, the decrease in average daily 

withdrawals from 1983 to 1995 is at least 62 percent. 

FIGURE 3C.Water-table configuration in Kings, Queens, and western Nassau Counties, N.Y., in 

1943. (From Buxton and Shernoff, 1999, fig. 7B.)
22 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Base modified from U.S. Geological Survey, 1:100,000;

Hydrography and cultural features modified to reflect

the period from 1943 through 1951

Atlantic Ocean

East

River

Flushing Bay

Flushing Creek

Little Neck

Bay

QUEENS

COUNTY

NASSAU

COUNTY

0 1 2 3 4 5 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS

COUNTY

40°45'

74°00' 73°45'

2

4

5

10

20

30

40

50

60

-5

-10

-15

-20

-25

0

EXPLANATION

0 WATER-TABLE CONTOUR – Shows altitude of water table. Contour

interval 2, 5 and 10 feet. Datum is sea level. Hachures indicate depression. 

This decrease is reflected in the recent (1996) water 

levels in Kings, Queens, and western Nassau Counties, 

as discussed below and depicted in figure 4. 

Kings County.—Data from Kings County are 

sparse, even though four new Jameco-Magothy aquifer 

wells were installed in 1994 and 1995, tripling the 

number of wells available for water-level 

measurements in this aquifer from two to six (fig. 4). 

Water levels at the two older wells in Kings County 

(K522 and K3132, fig. 4) in 1995 were similar to those 

in 1983 and are in agreement with the previously 

described equilibrium conditions in the upper glacial 

aquifer since 1983. The water level at the new well in 

central Kings County (K3431) in 1996 was 11.74 ft 

above sea level, which agrees with the 10-ft contour of 

1983 presented by Buxton and Shernoff (1995). The 

remaining three new wells are in coastal parts of Kings 

County, where water-level data are lacking. The water 

level in well K3406, in western Kings County, was 

about 3 ft above sea level in 1996. Wells K3407 and 

K3414, near the southern shore of Kings County, were 

screened in saline ground water. Density differences 

between fresh and saline ground water requires that a 

simple calculation be made on water levels measured 

in saline wells so that the adjusted water levels 

(freshwater equivalent head) can be compared to those 

FIGURE 3D. Water-table configuration in Kings, Queens, and western Nassau Counties, N.Y., 

in 1951. (From Buxton and Shernoff, 1999, fig. 7C.)
Recent (1992-97) Hydrologic Conditions 23

-5

-5

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS

COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

0 WATER-TABLE CONTOUR – Shows altitude of water table. Contour

interval 5 feet. Datum is sea level. Hachures indicate depression. 

5

15 10

20

25

30

35

40

45

5

5

5

10

10

15

20

20

25

50

0

-10

0

-5

-15

-5

-5

15

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

in freshwater wells. After correction to freshwater 

equivalent head, wells K3407 and K3414 had water 

levels of 10.30 and 8.45 ft above sea level, 

respectively, in 1996. The latter two nearshore wells 

indicate upward ground-water movement, which is 

consistent with the flow patterns in this area as 

indicated on plate 7 of Buxton and Shernoff (1995).

Queens County.—Recent (1992-97) water-level 

measurements were obtained from 12 of the 15 

Jameco-Magothy aquifer wells measured in Queens 

County in 1983; additional water-level data are 

available for three wells measured between 1983 and 

1992. Water levels in all 15 wells indicate that the 

potentiometric surface of the Jameco-Magothy aquifer 

has been recovering since 1983 in response to 

reductions in public-supply withdrawals (fig. 4). 

Specifically, water levels recovered at least 1.37 ft 

along the coast (well Q3150) and by almost 32 ft near 

the public-supply wells in central parts of the county 

(well Q2300). These data indicate that the 

potentiometric surface of the Jameco-Magothy aquifer 

is not below sea level in any part of Queens County; 

the water levels generally areabout 5 ft above sea level 

near the southern coast, and increase inland to about 

20 ft above sea level near western Nassau County.

Nassau County.—Water-level measurements 

made in 1983 and thereafter at eight wells screened in 

the Jameco-Magothy aquifer in western Nassau 

FIGURE 3E. Water-table configuration in Kings, Queens, and western Nassau Counties, N.Y., 

in 1961. (From Buxton and Shernoff, 1999, fig. 7D.)
24 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

0 WATER-TABLE CONTOUR – Shows altitude of water table. Contour

interval 10 feet. Datum is sea level. Hachures indicate depression. 

10

0

20

30

10

-10

10

10

County (fig. 4) are available. Recent (1992-96) water 

levels in wells farthest from the former cone of 

depression in Queens County are similar to, or slightly 

higher than in 1983, and water levels in all wells closer 

to the cone of depression are much higher than in 

1983. From 1983 through 1996, water levels at all 

Jameco-Magothy aquifer wells in Nassau County 

increased at least 2.7 ft and by as much as 18.6 ft.

Lloyd Aquifer

The potentiometric-surface map of the Lloyd 

aquifer in Kings, Queens, and western Nassau 

Counties in January 1983 (plate 6 of Buxton and 

Shernoff, 1995) shows water levels at 20 wells, only 

one of which is in Kings County. The most prominent 

feature on that map (not displayed here) is a large 

depression that originates in central Queens County 

FIGURE 3F. Water-table configuration in Kings, Queens, and western Nassau Counties, N.Y., in 

1974. (From Buxton and Shernoff, 1999, fig. 7E.)
Recent (1992-97) Hydrologic Conditions 25

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

0 WATER-TABLE CONTOUR – Shows altitude of water table. Contour

interval 5 feet. Datum is sea level. Hachures indicate depression. 

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

5

0

10

15

20

25

30

35

5

5

5

5

10

10

10

5 10

5

15

15

20

20

15

and extends into western Nassau and eastern Kings 

Counties. The -20-ft contour of this depression is 

centered around four public-supply wells (Q317, 

Q562, Q567 and Q3069, fig. 5) whose combined 

withdrawals averaged about 6 Mgal/d in 1983. The 

1983 water-level measurements were made several 

hours after the pumps were temporarily shut down; 

thus, the cone of depression probably extended deeper 

during typical withdrawal periods. Water levels 

measured in 1983 near the buried channel described 

previously indicate that ground water in this area flows 

downward through the units that fill the channel and 

into the Lloyd aquifer.

Recent (1996) water-level measurements in wells 

screened in the Lloyd aquifer indicate substantial 

recovery of the potentiometric surface since 1983 (fig. 

5). By 1996, water levels at the four public-supply 

wells mentioned earlier had recovered by at least 19 ft, 

and by as much as 35 ft, as a result of the 1994 

reduction of pumping to a combined total of about 

54,000 gal/d from these wells—less than 1 percent of 

the 1983 withdrawals. Water levels in every Lloyd well 

measured in the study area had partially recovered. 

Measurements from wells as far south as Jamaica Bay 

(Q287) and Rockaway Beach (Q1071) show waterlevel increases of about 6.5 ft. This rapid and 

FIGURE 3G. Water-table configuration in Kings, Queens, and western Nassau Counties, N.Y., in 

1981. (From Buxton and Shernoff, 1999, fig. 13A.)
26 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS

COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica B

KINGS COUNTY ay

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

0 WATER-TABLE CONTOUR – Shows altitude of water table. Contour

interval 5 feet. Datum is sea level. Hachures indicate depression. 

0

5

10

15

20

25

30

35 40 45

50

0

0

-10

-5

-5

5

5

5

5

5

5

10

10

10

10

15

15

15

20

20

20

20

20

25

25

30

30

15

widespread recovery is as expected for a relatively 

thin, confined aquifer. Additional water-level 

measurements were obtained from the four newly 

installed wells screened in the Lloyd aquifer (fig. 5)—

one in Kings County (K3410), and three in Queens 

County (Q3627, Q3628 and Q3593). The water level 

at well K3410, near the northern extent of the Lloyd 

aquifer, was about 8 ft above sea level in 1996; in 1983 

water levels were close to sea level (Buxton and 

Shernoff, 1995, pl. 6). Water levels at wells Q3627 and 

Q3628 in west-central Queens County, near the 

southern extent of the buried channel (fig. 5), were 

10.7 and 11.2 ft above sea level, respectively, in 1996; 

in 1983 they were near or at sea level. These latter data 

indicate a downward flow of ground water into the 

Lloyd aquifer, as in 1983. Recent (1992-97) data from 

western Nassau County are sparse and variable and, 

thus are not presented here.

Ground-Water Quality

This section describes recent (1992-96) waterquality conditions in Kings and Queens Counties and 

relates them to historical water-quality trends 

described in Buxton and Shernoff (1995). Emphasis is 

FIGURE 3H. Water-table configuration in Kings, Queens, and western Nassau Counties, N.Y., in 

1983. (From Buxton and Shernoff, 1999, plate 3.)
Recent (1992-97) Hydrologic Conditions 27

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

5 WATER-TABLE CONTOUR – Shows altitude of water table. Contour

interval 5 feet. Datum is sea level.

5

10

15

15

10

5

20

25

30

35

40

45

25

25

35

45

50

20

5

15

10

20

on nitrate and chloride concentrations, by aquifer, 

since 1983 and on results from the first extensive data 

set of organic-compound concentrations in ground 

water of Kings and Queens Counties (Cartwright and 

others, 1998). Locations of wells from which water 

samples were collected are shown in figures 6A 

through 6I; the general relations between chloride and 

nitrate concentrations in ground water, and withdrawal 

rates in Kings and Queens Counties, are summarized 

in table 4.

Chloride

Predevelopment concentrations of chloride in 

ground water on Long Island probably ranged from 

about 3 to 12 mg/L (Buxton and Shernoff, 1995), but 

by the early 1900’s, ground-water withdrawals in 

Kings and Queens Counties had caused saltwater 

intrusion in the upper glacial aquifer in coastal areas, 

where chloride concentrations as high as 500 mg/L 

were reported (Spear, 1912). New, deeper publicsupply wells were installed farther inland and 

FIGURE 3I. Water-table configuration in Kings, Queens, and western Nassau Counties, N.Y., 

in 1997.
28 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

7.2

6.2

Monitoring well - upper number is 1983

water level in feet above sea level,

lower number is 1996 water level:

Number in parentheses is water level

between 1983 and 1992.

K3406 NYSDEC well-identifier for well mentioned in text

ND No data available

.

8.5

9.3

7.2

6.2

ND

3.1

ND

10.3

ND

8.45

ND

11.7

13.2

16.8

-7.6

16.1

1.8

16.3

1.1

5.4

-5.4

(1.5)

3.8

(5.2)

-9.8

22.1

-3.5

(4.9)

-1.6

6.0

ND

5.7

1.5

3.8

2.4

5.6

-0.5

3.7 1.0

5.7

-0.2

(3.7)

2.5

8.5

1.1

3.8

-4.6

-4.7 ND

4.1

7.7

(12.9) 3.6

13.2

6.0

15.1

4.1

22.7

K3406

K3431

K522

K3407

K3132

Q3150

K3414

1.1

4.2

.

.

.

.

.

.

.

.

.

.

.

. .

.

. . .

. .

. . . .

.

. .

.

.

.

Q2300

eastward to avoid the migrating saltwater front but the 

number of supply wells contaminated with saltwater 

continued to increase through the 1940’s, even in the 

deeper Jameco-Magothy aquifer and at inland 

locations. The elevated chloride concentrations at 

some wells were probably due to surface-derived 

sources (mostly road salting), but no attempt was 

made to differentiate saltwater-derived chloride from 

surface-derived chloride. By 1947, chloride 

concentrations were as high as 700 mg/L at some 

inland wells, and as high as 8,000 mg/L at wells along 

the southern shore (Buxton and Shernoff, 1995). The 

history of the saltwater-front migration is outlined in 

table 4.

Figure 4. Ground-water levels in 1983 and 1996 in wells screened in the Jameco-Magothy 

aquifer in Kings, Queens, and western Nassau Counties, N.Y. (Modified from Buxton and 

Shernoff, 1995, pl. 5.)
Recent (1992-97) Hydrologic Conditions 29

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

.

1.1

5.6

.

.

.

.

. .

.

.

.

. .

. .

.

.

.

.

.4.3

6.9

1.91

7.0

-26.2

8.6

ND

ND

ND

8.0

-21.5

-2.1

-23.6

9.3

-26.8

ND 8.7

11.2

ND

10.7

1.5

13.2

-7.9

9.4

-10.2

6.8

4.6

8.4

-11.6

8.2

5.1

(10.2)

5.1

10.6

ND

5.2

-0.1

7.7

-4.7

8.0

K3410

Q3628

Q3627

Q317

Q3069

Q567

Q562

Q287

Q1071

-10.2

6.8

Monitoring well - upper number is 1983

water level in feet above sea level,

lower number is 1996 water level:

Number in parentheses is water level

between 1983 and 1992.

K3406 NYSDEC well-identifier for well mentioned in text

ND No data available

Northern limit of Lloyd aquifer in Queens County,

indicating the buried river channel where the

sediments of the Lloyd aquifer were eroded.

.

Rockaway Beach

{

Upper Glacial Aquifer

Kings County.—In 1983, chloride concentrations 

in water samples from 36 monitoring wells screened in 

the upper glacial aquifer ranged from 15 to 

1,100 mg/L (Buxton and Shernoff, 1995). Chloride 

concentrations in inland areas of Kings County show 

no discernible pattern; thus, no contours are depicted. 

The elevated chloride values in inland areas are 

probably the result of past saltwater intrusion as well 

as surface-derived contamination (Buxton and 

Shernoff, 1995). Most chloride values above 250 mg/L 

were in nearshore areas, particularly near natural or 

Figure 5. Ground-water levels in 1983 and 1996 at wells screened in the Lloyd aquifer in Kings 

and Queens Counties, N.Y. (Modified from Buxton and Shernoff, 1995, pl. 6.)
30 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Atlantic Ocean

East

River

Flushing Bay

Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

MONITORING WELL

PUBLIC - SUPPLY WELL - for which concentration

of nitrate or chloride is available

.

.

K3275

Q1843

Q301

Q303 Q304

Q307

Q308

Q310

Q313

Q322

Q323

Q558

Q1450

Q1747

Q1811

Q1840

Q1843

Q1997

Q2000

Q2001

Q2138 Q2027

Q2189

Q2299 Q2275

N14

N693

N2115

N2414

N4077

N5155 N6744

Q1189 Q1506 Q2324 Q2993

Q2994

Q2995 Q3114

Q3115

Q3117 N1429

N1627

K2610

K2622

K3255

K3256

Q1605

Q1663

Q2407

Q2418 Q2814

Q3123

Q3134

K1673

K1678

K1689

K2040

K2407

K2412

K2482

K2591

K2598

K3151

K3214

K3216

K3218

K3242

K3245

K3246

K3249 K3247

K3250

K3251

K3252

K3253 K3254

K3257

K3260

K3267

K3272

K3273

K3275

K3276

Q2656

K3248

Q1930

N6792

Q3121 Q2791

Q2978 Q3119

N8877

K3271

.

.

. .

.

. .

. .

.

.

.

.

.

.

.

.

.

.

.

.

. .

. .

.

.

. .

.

.

.

.

. .

.

. . . .

.

.

.

.

.

. . .

.

. .

.

.

.

.

.

. .

.

.

.

.

. .

.

.

.

. .

. .

.

.

. .

. . . .

..

. . .

.

.

. .

.

.

73°45'

manmade coastal embayments. An isolated 

concentration of 1,100 mg/L at a well about 3 mi from 

Jamaica Bay and about 1.5 mi from the nearest 

saltwater embayment is probably from a surface 

source. Historical concentrations of chloride in the 

upper glacial aquifer in 1947, 1961, 1970, 1981, and 

1983, in Kings County are indicated in figures 7A 

through 7E, respectively.

Chloride concentrations at the majority of wells 

(74 percent) screened in the upper glacial aquifer in 

Kings County have remained steady or have declined 

since 1983. Chloride concentrations at 23 wells from 

which 1983 and 1996 data are available remained 

nearly constant at 1 well, decreased at 16 wells, and 

increased at 6 wells (figs. 7E, 7G). Of the six wells at 

which chloride concentrations increased, three are 

within 0.5 mi of the shore (K2412, K1407, K3250) 

with concentrations of 41 to 1,000 mg/L, and three are 

1 to 1.5 mi from a saltwater body (K3242, K3275, 

K1678) with concentrations of 55 to 470 mg/L. Waterquality data also were collected at eight other upper 

glacial wells in Kings County in 1983 and 1992, but 

not in 1996; chloride concentrations remained 

constant at two wells, declined at four wells, and 

increased at two wells. Well K3245 is 0.75 mi from 

Newtown Creek, in the northeastern part of the county 

FIGURE 6A. Locations of wells screened in the upper glacial aquifer in Kings, Queens, and 

western Nassau Counties, N.Y., from which ground-water samples were collected in 1983. 

(Modified from Buxton and Shernoff, 1995, fig. 12A.)
Recent (1992-97) Hydrologic Conditions 31

Atlantic Ocean

East

River

Flushing Bay

Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

.K1189

Q2332 .

MONITORING WELL

PUBLIC – SUPPLY WELL

K922

K1189

K2510

K2582

K3132 K3130

K3133

Q277

Q471

Q1187

Q2384

Q2426

Q3109

Q3110

Q3112 Q3150

N3932

N4213

N6581

N7161

Q311

Q314

Q564

Q566 Q568

Q1600 Q1629

Q1815

Q1957

Q1958

Q2026

Q2028

Q2137

Q2188

Q2243

Q2276 Q2300

Q2332

Q2343 Q2362

Q2363

Q2373

Q2374

Q2408

Q2409

Q2432

Q2435

Q2955

Q3014 Q3034

Q3062 Q3083

N11N12 N13

N17

N2413 N3720

N4298

N4390

N4512

N5156

N6745

N7445

N7649

N7650

K2511

Q1237

Q1472 Q1914

Q2289

Q3003

Q3015

N3864

N4062

N6703

N6707

Q2442

N7482

N3867

N4026

N6701

Q2443

{

{

{

{

{

{

.

. .

.

.

. .

. ..

.

..

.

..

. .

.

.

. .

. .

.

.

.

.

.

.

.

.

.

.

.

. . .

.

. . .

. . .

. . .

.

.

.

.

.

.

.

.

. .

.

.

.

. ...

. .

.

. .

..

.

.

73°45'

(figs. 7F, 7G), and well K3257 is in east-central Kings 

County, where the elevated concentrations probably 

are due to surface-derived contamination. 

The chloride-concentration data presented in this 

report indicate that the upper glacial aquifer in Kings 

County is being flushed of saline water from past 

saltwater encroachment. This process probably has 

been occurring since about 1974, when water levels in 

Kings County recovered to 1903 levels. This flushing 

is further supported by the 1997 water levels, which 

indicate seaward gradients throughout the county. 

Increasing chloride concentrations since 1983 at upper 

glacial wells in nearshore areas may be due to 

incomplete flushing, and those farther inland are 

probably a result of surface-derived contamination. 

Five additional wells screened in the upper 

glacial aquifer installed in Kings County during this 

investigation have provided chloride data for 1995 and 

(or) 1996. One of these wells (K3406) is on the East 

River at the western edge of Kings County (fig. 7G); it 

is screened just above bedrock (possibly in the Jameco 

aquifer) but is representative of shallow ground-water 

quality in this area because no overlying confining unit 

was observed. The chloride concentration in water 

FIGURE 6B. Locations of wells screened in the Jameco-Magothy aquifer in Kings, Queens, 

and western Nassau Counties, N.Y., from which ground-water samples were collected in 1983. 

(Modified from Buxton and Shernoff, 1995, fig. 13A.)
32 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Atlantic Ocean

East

River

Flushing Bay

Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

.

.

K2859

Q273

Q470

Q1071

Q1241

Q1373

Q2419

Q2420

Q3036

N6701

Q317 Q562

Q565

Q567

N1958

Q287

{

. .

.

.

. .

. . .

.

.

.

.

.

.

K2859

Q3036

MONITORING WELL

PUBLIC – SUPPLY WELL

73°45'

from this well in 1995 was 520 mg/L and indicates 

that the well is screened within a zone of diffusion. 

This indication is supported by an electromagnetic 

(EM) log, which indicates a 10-ft zone of saline water 

at the base of the well (Chu and Stumm, 1995). The 

other four wells (K3405, K3424, K3425 and K3430) 

are further inland with chloride concentrations of 57, 

14, 91, and 90 mg/L, respectively, in 1996. These 

values are typical of the upper glacial aquifer in Kings 

County and are probably due to past saltwater 

encroachment in the Flatbush Franchise area of the 

former JWS (fig. 1), although they also could be partly 

due to surface-derived contaminants.

Queens County.—The 1983 chloride 

concentrations in all of Queens County at 22 

monitoring wells and 23 public-supply wells screened 

in the upper glacial aquifer ranged from 17 to 9,000 

mg/L, whereas concentrations in inland areas ranged 

only from 31 to 160 mg/L. The 160-mg/L 

concentration at public-supply well Q2189 (fig. 6A 

and 7E) is near the center of a cone of depression that 

developed around the Woodhaven Franchise area in 

southwestern Queens County (fig. 3E) in the 1960’s 

and, therefore, may reflect residual chloride from 

saltwater intrusion.

Recent (1992 and 1996) data from Queens 

County indicate that chloride concentrations at most 

FIGURE 6C. Locations of wells screened in the Lloyd aquifer in Kings, Queens, and western 

Nassau Counties, N.Y., from which ground-water samples were collected in 1983. (Modified 

from Buxton and Shernoff, 1995, fig. 14A.)
Recent (1992-97) Hydrologic Conditions 33

Atlantic Ocean

East

River

Flushing Bay

Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

K1678

K1689

K2482

K3214

K3216

K3218

K3242

K3252

K3253 K3254

K3276

K1673

K3273

K2412

K3248

K3275

K2407

K3251

K2622

K3151

K3246

K3255

K3257

K3256 K2610

K3271 Q1189 Q2324 Q2994

Q2995 Q3114

Q3115

Q3117 N1429

N1627

Q2138

Q558

K2598

K3245

Q1605

Q1663

Q1930

Q2656 Q2407

N6792

N5155

N693

N6744 Q307

Q318

Q1747

Q1843

Q2001

Q2418

Q2791

Q2814

Q2978

Q3119 Q3121

Q3134

N8877

Q1840 Q303

K3250

K3267

K3249

Q301

Q303

Q2189 N2414

Q310

Q323

Q2321

Q2275

Q2299

Q2027

Q563

Q305 Q1997

Q2000

Q321 Q313 N14

N4077

.

.

.

. .

.

. .

.

.

.

.

.

.

.

.

.

. .

. .

.

. .

.

.

.

.

.

. .

. .

.

.

. .

.

.

.

.

. .

.

. .

. .

.

. . .

.

. .

. .

. .

. ..

.

.

..

. . .

.

.

. .

.

.

. .

.

.

.

.

.

MONITORING WELL

PUBLIC – SUPPLY WELL

K2482

Q2187

73°45'

.

wells screened in the upper glacial aquifer have 

declined or remained steady since 1983 (figs. 7E, 7F, 

and 7G). Chloride concentrations have remained 

constant at 1 of 16 wells for which 1983 and 1996 

chloride data are available, have decreased at 11 

wells, and have increased at 4 wells. Of the four 

wells at which chloride concentration increased, 

Q3117 had a value of 160 mg/L in 1996 and is in 

southern Queens County in an area likely to be 

affected by previous public-supply withdrawals from 

JWS wellfields; Q2656 and Q2978 are in northern 

Queens County with chloride concentrations of 24 

and 32 mg/L, respectively, in 1996, and Q2407 is in 

central Queens County with a chloride concentration 

of 93 mg/L. These concentrations are relatively low 

and, except for the value at Q3117 (160 mg/L) in 

southern Queens County, probably do not reflect past 

saltwater intrusion. 

In addition to the 16 wells for which 1983 and 

1996 data are available, 7 other wells screened in the 

upper glacial aquifer in Queens County were sampled 

in 1983 and 1992. Chloride concentrations at five of 

these wells increased, and those at two wells 

decreased. Of the five wells with higher chloride 

concentrations in 1992 than in 1983, four are publicsupply wells in southern Queens (Q558, Q1747, 

Q2001, Q2138) and may reflect residual effects of 

long-term, widespread withdrawals, and one is a 

FIGURE 6D. Locations of wells screened in the upper glacial aquifer in Kings, Queens, and 

western Nassau Counties, N.Y., from which ground-water samples were collected in 1992.
34 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Atlantic Ocean

East

River

Flushing Bay

Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

.

.

MONITORING WELL

PUBLIC – SUPPLY WELL

K2582

Q2332

K2510

K2582

K3133

Q277

Q471

Q1237 Q1187

Q1472 Q1914

Q3003

Q3109

Q3110

Q3112

N3864

N3867

N3932 N4026

N4062

N4213

N6581

N6701

N6703

N6707

N7161

Q2955

Q566

Q1629

Q2188

Q2028

Q2332 Q2276

Q564

N17

N3720

N4512

N4390

N7649

N11643

N10206

N11037

N10207

N7482

N10211

N4298

N7445

N5156

N6745

N7650

Q311

Q314 Q2026

Q2373

Q2362

Q2363 Q2408

Q2442

Q3034

Q3014

Q3062

Q1958

Q1600

Q2435

Q1815 Q568

Q2432 Q2300Q2343

Q1957

Q2374

Q2409

Q2443

N11

{

{

{ {

}

{

{

{

{

{

.

.

. .

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

. .

.

.. .

.

.

.

.

.

. .

. .

.

. . .

.

.

. .

. .

.

.

.

.

.

.

.. .

.

.

73°45'

monitoring well (Q2418) in northern Queens County, 

about 0.5 mi from an embayment of the East River, 

where localized saltwater contamination is likely. 

Chloride concentrations of the four public-supply 

wells ranged from 56 to 92 mg/L in 1992, and that at 

the monitoring well in northern Queens County 

(Q3121) was 140 mg/L. Two of the seven wells 

showed a decline in chloride concentrations during 

1983-92; the 1992 concentration at a public-supply 

well in east-central Queens County (Q307) was 

4 mg/L, and that at a monitoring well, less than 0.5 mi 

from a saltwater embayment in north-central Queens 

(Q2418), was 320 mg/L. Chloride concentrations in 

the majority of upper glacial aquifer wells in Queens 

County indicate an overall decrease in chloride 

concentration from past saltwater intrusion. The nine 

wells at which chloride increased after 1983 are either 

near a saltwater body, or are in inland areas with 

chloride concentrations less than 100 mg/L. 

Most of the 11 additional wells installed in the 

upper glacial aquifer in Queens County for this 

investigation are in inland parts of the county, where 

data were lacking; some were installed as the shallow 

well of a well cluster, and others were installed near 

the coast for saltwater monitoring. Chloride 

concentrations in 1996 at these 11 wells ranged from 

10 to 96 mg/L, a range comparable to that in Kings 

County, and also may reflect past saltwater 

FIGURE 6E. Locations of wells screened in the Jameco-Magothy aquifer in Kings, Queens, and 

western Nassau Counties, N.Y., from which ground-water samples were collected in 1992. 
Recent (1992-97) Hydrologic Conditions 35

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

.

.

MONITORING WELL

PUBLIC – SUPPLY WELL

K2859

K2859

Q273

Q287

Q470

Q1071

Q1373

Q2419

Q2420

Q3036

Q317

Q567

Q565 Q562

{

Q3657

N1958

. .

.

.

.

.

.

.

. .

.

.

.

.

Q273

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

encroachment or surface-derived contamination. Wells 

Q3587 and Q3649 are a doublet (two wells installed at 

the same location, but screened at different depths) in 

west-central Queens County; Q3587 is screened from 

72 to 82 ft below sea level, and Q3649 from 12 to 22 ft 

below sea level. Chloride concentrations at the two 

sampled depths do not differ appreciably, nor did they 

change significantly from 1995 to 1996; measured 

1995 and 1996 concentrations at Q3649 were 86 and 

71 mg/L, respectively; those at Q3587 were 75 and 

88 mg/L, respectively. Of the 11 new wells screened in 

the upper glacial aquifer, chloride concentrations in 

the six inland wells (Q3629, Q3650, Q3651, Q3659, 

Q3660, and Q3661) were 10, 87, 69, 73, 56, and 

39 mg/L, respectively. These values are typical of 

urbanized areas of Kings and Queens Counties and 

probably are the result of surface-derived 

contamination. The 2 wells with the highest chloride 

concentrations of all 11 new wells are Q3604, on the 

northern coast of Queens County and screened from 

27 to 37 ft below sea level, and well Q3658, in 

southern Queens County and screened from 10 to 15 ft 

below sea level. Chloride concentrations in 1996 for 

these two wells were 96 mg/L and 100 mg/L, 

respectively. Comparison of these values with 

background levels from 3 to 12 mg/L (Buxton and 

Shernoff, 1995), indicates some saltwater 

contamination, but neither the source nor the time of 

FIGURE 6F. Locations of wells screened in the Lloyd aquifer in Kings, Queens, and western 

Nassau Counties, N.Y., from which ground-water samples were collected in 1992. 
36 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Atlantic Ocean

East

River

Flushing Bay

Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

.

.

MONITORING WELL

PUBLIC – SUPPLY WELL

K3276

Q2189

.

.

.

.

.

.

.

. . . .

..

. . .

.

.

.

. . . .

. .

. .

.

.

.

.

.

.

. .

.

. .

.

.

. .

.

.

.

.

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.

.

. . .

.

.

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.

.

.

.

.

.

.

. .

.

. .

. ..

.

.

K3424

K1673

K1678

K1689

K2407

K2412

K2482

K2598

K2610

K2622

K3151

K3214

K3218

K3242

K3246

K3248

K3250

K3251

K3252

K3253 K3254

K3267

K3275

K3276

K3405

K3406

K3425

K3430 N1627

N6792

N8877

Q1189

Q1663

Q1930

Q2324

Q2418

Q2656

Q2791

Q2814

Q2978

Q2995

Q3114

Q3115

Q3117

Q3119

Q313

Q3604

Q3629

Q3644

Q3646

Q3648

Q3649

Q3650

Q3651

Q3652

Q3658

Q3660

Q3661

N4077

Q305 N5155

Q310

Q313

Q321

Q1747

Q1997

Q2189

Q2407

Q2994

Q3587

Q3659

N2414

N6744

{

73°45'

occurrence is certain. Geophysical logs of the deeper 

well, Q3593 (Chu and Stumm, 1995), indicate a 

shallow zone of elevated electrical conductivity from 

background levels in the upper glacial aquifer and a 

deeper zone of lower electrical conductivity in the 

confined Lloyd aquifer, suggesting the presence of a 

saltwater wedge within the upper glacial aquifer. 

Chloride concentrations in the shallow and deep zones 

in 1995 were 110 and 8.9 mg/L, respectively, and are 

consistent with the data from the geophysical logs. 

The presence of brackish water in the upper glacial 

aquifer near the northern shore of Queens County 

probably does not present a problem of widespread 

contamination, however, because the aquifers in this 

area are thin and unlikely to ever be developed.

Jameco-Magothy Aquifer

Kings County.—The range of chloride 

concentrations in 1983 at eight Jameco-Magothy 

aquifer wells in Kings County was from 140 to 

18,000 mg/L; this includes wells screened in formerly 

salty ground water with residual chloride 

concentrations, and wells screened in salty ground 

water in 1983 (Buxton and Shernoff, 1995, fig. 13A). 

Data are too sparse to allow contouring; nevertheless, 

chloride concentrations in the two southernmost wells 

FIGURE 6G. Locations of wells screened in the upper glacial aquifer in Kings, Queens, and 

western Nassau Counties, N.Y., from which ground-water samples were collected in 1995-96. 
Recent (1992-97) Hydrologic Conditions 37

Atlantic Ocean

East

River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

.

.

MONITORING WELL

PUBLIC – SUPPLY WELL

K3133

Q2332

K2510

K2511

K2582

K3133

K3407

K3414

K3431

N3864

N3867

N3932

N4026

N4062

N4213

N6581

N6701

N6703

N6707

N7161

Q277

Q471

Q1237

Q1472 Q1914

Q3003

Q3109

Q3110

Q3112

Q3589

N7482 N3720

N4298

N7445

N5156

N7650

Q314 Q2026

Q2373 Q2408

Q2955

Q3014

Q3062

Q1958

Q2435

Q568

Q2432

Q2332 Q2276

Q1957 Q2409 Q2188

N17

N7649

N11037 N10206

N6745

}

{

{

{

Q2300

{

{

{

N10207

N11

{

.

.

.

.

.

. .

. .

.

.

.

.

.

. .

. .

.

.

.

.

.

.

. . . . . ..

. .

.

..

.

.

.

.

.

..

.

.

.

.

.

. .

.

73°45'

(K2510 and K2511) are elevated from background 

concentrations; each of these wells is screened about 

200 ft below sea level near the coast at Coney Island 

(fig. 8A). Elevated chloride concentrations at these 

wells (16,000 and 18,000 mg/L, respectively) indicate 

that the freshwater-saltwater interface in the JamecoMagothy aquifer is farther inland than in the upper 

glacial aquifer. The toe of this interface in 1983 was 

estimated to be about 1 mi inland (Buxton and 

Shernoff, 1995). 

Recent (1992 and 1996) water-quality data from 

the Jameco-Magothy aquifer in Kings County (figs. 

8B, 8C) are relatively sparse in relation to data 

available for the upper glacial aquifer because fewer 

wells are available for sampling. Only five JamecoMagothy aquifer wells provide chloride data from 

1983 and 1996—wells K2510 and K2511, along the 

southern shore; K3407, about 1 mi inland from wells 

K2510 and K2511; well K2582, in south-central 

Kings County; and well K3133, in northern Kings 

County. The chloride concentration in 1992 and 1996 

at well K2510 was 16,000 mg/L, and that at well 

K2511 in 1996 was 16,000 mg/L. These wells are not 

screened at the freshwater-saltwater interface and, 

therefore, do not provide information on interface 

extent and movement. A decrease in chloride 

FIGURE 6H. Locations of wells screened in the Jameco-Magothy aquifer in Kings, Queens, 

and western Nassau Counties, N.Y., from which ground-water samples were collected in 

1995-96. 
38 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Atlantic Ocean

East

River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

.

.

MONITORING WELL

PUBLIC – SUPPLY WELL

K3410

Q3036

K3410

K3426

Q287

Q470

Q1071

Q1373

Q2419

Q2420

Q3036

Q3593

Q3627

Q3628

N1958

Q567

Q2300 }

{

.

.

.

.

.

.

.

.

.

.

.

.

.

73°45'

concentration at well K2511 from 18,000 mg/L in 

1983 to 16,000 mg/L in 1996 may indicate flushing of 

the system since the recovery of water levels to 

elevations above sea level since the early 1960’s. This 

theory is supported by continually decreasing chloride 

concentrations at well K2582, about 3.5 mi inland 

(figs. 8A-C) from 170 mg/L in 1983 to 140 mg/L in 

1992 and to 47 mg/L in 1996. In contrast, chloride 

concentrations at well K3133 (figs. 8A-C) in northern 

Kings County increased from 140 mg/L in 1983 to 

180 mg/L in 1992 and to 300 mg/L in 1996; this well 

is about 1.25 mi from the saline waters of the East 

River and 1 mi from Newtown Creek, and where 

aquifers are thin. High chloride concentrations at this 

well are, therefore, probably the result of saltwater 

migration from either or both of these water bodies in 

response to unidentified local withdrawals.

Three additional Jameco-Magothy wells (K3414, 

K3407, and K3431) were installed in Kings County 

for this study (fig. 4). The first two were installed in 

the southern part of the county to help define the depth 

and northern extent of the saltwater interface. Well 

K3414 is along the coast near wells K2510 and K2511 

but is screened deeper (283 to 303 ft below sea level), 

and well K3407 is about 1 mi inland of wells K2510 

and K2511 at the estimated northern extent of the 

1983 saltwater interface; it is screened from 246 to 

266 ft below sea level. The 1996 chloride 

FIGURE 6I. Locations of wells screened in the Lloyd aquifer in Kings, Queens, and western 

Nassau Counties, N.Y., from which ground-water samples were collected in 1995-96.
Recent (1992-97) Hydrologic Conditions 39

Base modified from U.S. Geological Survey, 1:100,000;

Hydrography and cultural features modified to reflect

the period from 1943 through 1951

Atlantic Ocean

East

River

Flushing Bay

Flushing Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

0 1 2 3 4 5 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

.

.

.

. . . . . .

. .

.

. .

. . . .

.. . . . ..

. ...

....

. ... ...

. ..

.

.

.

.

.

.

.

.

.

CHLORIDE CONCENTRATION,

IN MILLIGRAMS PER LITER

EXPLANATION

LESS THAN 40

40 TO 250

MORE THAN 250

.

.

.

. .

.

.

.

. .

.

.

. .

.

.

.

..

.

.

. .. .

.

.

.

.

.. . .

.

.

.

. .

.

.

.

.... . .

. .

.

. .

.

.

.

.

.

.

.

.. . . .

.

.

.

.

.

.

. .

.

.

.

.

. .

.

. .

.

.

.

.

.

.

.

.

.

. .

.

. ..

.

.

.

.

.

.

.

. .

. .

.

.

.

. .

. . ..

. .

.

.

.

.

. .

.

.

.

. . .

.

.

.

.

.

.

.

.

..

. .

..

. . .

. ..

.

.

concentration at K3414 was 15,000 mg/L, slightly 

lower than at the two shallower wells at this site, 

which may indicate that saltwater has moved farther 

inland at a shallower depth in the Jameco aquifer, 

where horizontal hydraulic conductivity generally is 

greater than in the deeper Magothy aquifer. The 1996 

chloride concentration at well K3407 was 

16,000 mg/L, which strongly indicates that the 

freshwater-saltwater interface is farther inland than 

previously estimated, about 1.5 mi from the shore. In 

addition, geophysical logs from wells K3414 and 

K3407 (Chu and Stumm, 1995) indicate the thickness 

of a saltwater wedge at each site to be about 215 ft and 

about 155 ft, respectively. The slight decrease in 

chloride concentrations in this area since 1983 could 

indicate that the interface was even farther inland in 

1983. The third new well (K3431) is screened from 

274 to 294 ft below sea level in central Kings County 

FIGURE 7A. Chloride concentration in the upper glacial aquifer in Kings, Queens, and western 

Nassau Counties, N.Y., in 1947. (Modified from Buxton and Shernoff, 1995, fig. 9A.)
40 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

.

CHLORIDE CONCENTRATION,

IN MILLIGRAMS PER LITER

LESS THAN 40

40 TO 250

MORE THAN 250

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

. ....

.

.

.

.

.

. .

.

.

.

.

.. .

. .

.

. .

.

.

.

. . . .

. . .

.

.

.

.

.

. .

. .

.

. .

.

. .

.

.

.

.

. ..

.

.

..

.

..

.

.

. .

.

...

.

. .

..

.

.

. . .

.

.

.

.

. .

.

.

. . .

.

.

. . .

.

.

.

.

.

.

.

and appears to have been unaffected by saltwater 

intrusion; the chloride concentration at this well in 

1996 was 26 mg/L.

Queens County.—The 1983 chloride 

concentrations in Queens County at 15 monitoring 

wells and 34 public-supply wells screened in the 

Jameco-Magothy aquifer (fig. 8A) ranged from 6 to 

15,000 mg/L (Buxton and Shernoff, 1995). Chloride 

concentrations at most inland wells were less than 

100 mg/L, and many were between 20 and 30 mg/L. 

These concentrations are lower than those at the three 

inland wells in Kings County; this difference is 

attributed to the practice of shifting pumping stations 

eastward and inland to avoid saltwater intrusion that 

occurred from the 1930’s to 1974 (Buxton and 

Shernoff, 1995). Despite this practice, however, saline 

FIGURE 7B. Chloride concentration in the upper glacial aquifer in Kings, Queens, and western 

Nassau Counties, N.Y., in 1961. (Modified from Buxton and Shernoff, 1995, fig. 9B.)
Recent (1992-97) Hydrologic Conditions 41

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

.

CHLORIDE CONCENTRATION,

IN MILLIGRAMS PER LITER

LESS THAN 40

40 TO 250

MORE THAN 250

.

.

.

.

.

. .

. .

.

.

.

.

.

.

.

.

.

.

..

.

.

. . .

..

. .

.

..

.

.

.

. . .

.

.

.

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.

. .

. .

.

.

.

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.

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.

. .

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.

. . .

.

.

.

.

.

.

.

. . .

.

.

.

.

.

.

.

water was drawn into coastal areas of southern Queens 

County, where chloride concentrations at six wells in 

1983 ranged from 330 to 15,000 mg/L. 

Recent (1992-96) water-quality data for the 

Jameco-Magothy aquifer in Queens County are more 

extensive than those for Kings County (figs. 8B, 8C), 

mostly because Queens County contains many publicsupply wells from the former JWS. Chloride data for 

1996 are available for only 12 of the 34 public-supply 

wells sampled in 1983, however, because many of 

these were shut down as a result of the recent decrease 

in pumping for public supply. An additional six publicsupply wells provide chloride data for 1983 and 1992. 

Chloride values from 1996 also are available for 10 of 

15 monitoring wells sampled in 1983. Of the 28 

public-supply and monitoring wells, 15 showed 

increasing chloride concentrations, 8 showed little or 

no change, and 5 showed decreases. Most wells at 

FIGURE 7C. Chloride concentration in the upper glacial aquifer in Kings, Queens, and western 

Nassau Counties, N.Y., in 1970. (Modified from Buxton and Shernoff, 1995, fig. 9C.)
42 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

ND

. 134

.

MONITORING WELL - number is chloride concentration in mg/L.

PUBLIC – SUPPLY WELL - number is chloride concentration in mg/L.

No Data Available

52

75

93

700

134

1325

70

80

125

60

104

230

21

70

100

250

100

166

480

93

ND

196

196

12

82

103

376

13

62

45

>500

550

42

52

115

19

47

52

47 6

325

155

79

23

41

26

2

30

87

64

52

63

90

102

79

32

45

46

40

40

43

63

63

54

32

68

48

64

58 53

76 28

46 34

44

90

84

90 95

160

690

850

233 139 470

157

61

42

55

560

1340 69 {

.

.

.

. .

.

. .

.

.

. . . ..

. .

. . .

.

. .

.

.

. . .

. .

.

.

.

. .

. .

. .

.

. . ..

.

.

. .

. .

.

.

.

.

.

.

.

. . . .

.

.

.

. .

.

. . . ..

.

. . .. .

.

. .

. . .

. .

. .

.

.

which chloride concentrations increased are in inland 

areas, and the concentrations are relatively low—from 

11 to 47 mg/L. These small increases from 1983 

values probably do not indicate saltwater intrusion 

because the concentrations are low, and withdrawals 

for public supply have been diminishing, thereby 

lessening the likelihood of saltwater intrusion into 

inland areas. The concentration increases are more 

likely to be the result of contamination from surface 

sources in areas where the Gardiners Clay is absent. 

Four wells with high chloride concentrations are 

Q3110, Q3109, Q1237, and Q3112 in southern 

Queens County (fig. 6E), near the 1983 estimated 

position of the freshwater-saltwater interface (Buxton 

and Shernoff, 1995). Well Q3110 is the southernmost 

well; it is less than 0.5 mi from the coast and is 

screened from 296 to 316 ft below sea level. The 

chloride concentrations were 2,300 mg/L in 1983, 

2,500 mg/L in 1988, and 2,600 mg/L in 1992 (fig. 8B). 

The 1996 chloride concentration, estimated from a 

specific conductance measurement, is about 

2,950 mg/L. The steady increase in chloride 

concentration at this well since 1983 could indicate 

landward migration of saltwater through 1996, 

possibly as a result of continued (but decreased) 

withdrawals from the JWS Jamaica operations. Well 

FIGURE 7D. Chloride concentration in the upper glacial aquifer in Kings, Queens, and western 

Nassau Counties, N.Y., in 1981. (Modified from Buxton and others, 1981, fig. 23.)
Recent (1992-97) Hydrologic Conditions 43

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

96

30

72

94

39

68

210

250

500

210

73

51

120

40

170

140

280

47

81

29

38

26 82

270

85

31

360

16

170

71

15

50

1700

120

51

9000

140

57

490

17

71

69

25

25 44

72

1800

95

240 66

73

500

23 35

13

18

70

69

ND

34

86

88

31

50

51

50

60

64

ND

68

52

67

41 58

44 45

26

48

56

16

25

31

110

1100

560

140

340

65

76

160

24

70

{

.50

.

MONITORING WELL - number is chloride concentration in mg/L.

PUBLIC – SUPPLY WELL - number is chloride concentration in mg/L.

No Data Available

160

. .

.

.

.

. .

.

.

.

. .

.

.

.

.

. .

.

. .

. .

.

. .

. .

.

.

. .

.

.

.

.

.

.

.

.

.

.

.

.

.

. .

.

.

.

. .

. . . .

.

.

. .

.

.

. .

. .

. . . ..

. .

.

. .

.

.

. .

.

.

.

. .

. ..

.

.

ND

Woodhaven

Franchise Area

Q3109 is farther from the coast than well Q3110, is 

shallower (screened from 267 to 287 ft below sea 

level), and had higher chloride concentrations in 1983, 

1988, 1992, 1995—6,400, 4,700, 3,200, and 

3,200 mg/L, respectively (Chu and Stumm, 1995) and 

4,700 mg/L in 1996. The higher concentrations at well 

Q3109 than at well Q3110, along the southern shore, 

probably reflect this well’s proximity to the past cone 

of depression associated with JWS Woodhaven 

operations. The well’s proximity to a saltwater canal is 

not a factor because the canal does not penetrate the 

confined Jameco-Magothy aquifer. Well Q3109 shows 

a decrease in chloride concentrations during 1983-92 

and stabilization in these values by 1995. The 1996 

concentration was elevated (4,700 mg/L), possibly as a 

result of unidentified withdrawals in the area; the 1996 

value could be in error, however, because the specific 

conductance and sodium concentration in 1996 were 

the same as in 1992. A 1994 EM log of this well 

indicates a 70-ft thick saltwater zone (from 37 to 

107 ft below sea level) in the upper glacial aquifer. The 

peak EM response exceeded 600 mS/m, which 

corresponds to a chloride concentration of about 

6,000 mg/L (Chu and Stumm, 1995). The EM log also 

Figure 7E. Chloride concentration in the upper glacial aquifer in Kings, Queens, and western 

Nassau Counties, N.Y., in 1983. (Modified from Buxton and Shernoff, 1995, fig. 12A.)
44 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

.34

.

MONITORING WELL - number is chloride concentration in mg/L.

PUBLIC – SUPPLY WELL - number is chloride concentration in mg/L.

No Data Available

61

.

.

.

.

.

. .

. .

. . .

.

.

.

.

.

.

.

.

.

.

. . .

.

.

.

. . . . .

. .

. . .

.

.

.

.

.

.

.

. . .

.

.

. .

.

.

.

.

. .

. .

. ..

550

ND

560

44

200

120

100

52

15

82

650

23

26

10 21

10

62

170

83

78 110

130

130

110

41

250

160

83

34

84

81

98

320

19

74

140

160

4 2

56

50

92

85

61

67

42 160

230

150 32

8800

260 190 170 65

1400

210 30 18

9

27 47 29

7

ND

indicated an 80-ft-thick saltwater zone (from about 

192 to 272 ft below sea level) in the Jameco-Magothy 

aquifer with a peak EM response of about 300 mS/m; 

the 1995 chloride concentration at the screen zone was 

3,200 mg/L. The two other Jameco-Magothy aquifer 

wells (Q1237 and Q3112) are slightly farther north, 

near the generalized inland extent of the freshwatersaltwater interface of Buxton and Shernoff (1995). 

Well Q1237 is screened from 0 to 200 ft below sea 

level and sampling indicates that chloride 

concentrations increased—from 330 mg/L in 1983 to 

370 mg/L in 1992 and to 460 mg/L in 1996. The 

reason these values were higher than those at well 

Q3112, about 1.5 mi seaward of well Q1273, 

(110 mg/L in 1983, 140 mg/L in 1992, and 120 mg/L 

in 1996), is that the samples from well Q3112 were 

from the upper glacial aquifer as well as the JamecoMagothy aquifer.

A new Jameco-Magothy aquifer well (Q3589) 

was installed in 1994 in southern Queens County 

FIGURE 7F. Chloride concentration in the upper glacial aquifer in Kings, Queens, and western 

Nassau Counties, N.Y., in 1992. 
Recent (1992-97) Hydrologic Conditions 45

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

.41

.

MONITORING WELL - number is chloride concentration in mg/L.

PUBLIC – SUPPLY WELL - number is chloride concentration in mg/L.

NO DATA AVAILABLE

CHLORIDE CONCENTRATION IN 1995

78

ND

(66)

.

.

.

.

.

. .

. .

. . .

. .

.

.

.

.

..

. .

.

. .

.

.

. .

.

.

.

.

.

. . .

.

.

.

.

.

.

.

.

.

.

.

.

.

.

. .

.

.

.

.

. .

.

.

.

. .

.

.

48

470

59

630

41

98

14

62

100

55

64

16

1000

18

27

13 50

10

190

41

57

520

91

90 450

ND

ND

ND

40

5600

ND

ND

24

36

76

32

ND

58

1700

160

190

69

96

(10)

60

220

71

87

(66)

ND

100

73

56

39

19

109

29

34

43

74

78

30

140

93

ND

88

170

72

{

{

Newtown

Creek

about 0.5 mi north-northeast of well Q1237 and is 

screened from about 167 to 177 ft below sea level 

(fig. 6H). Chloride concentrations during 1992-96 

averaged about 67 mg/L. The EM log indicates a small 

(about 5-ft-thick) saltwater zone at the base of the 

upper glacial aquifer, and no saline water in the 

Jameco-Magothy aquifer (Chu and Stumm, 1995). 

These data, together with the water-quality and 

geophysical data from nearby well Q3109, indicate 

that the saltwater wedge in the upper glacial aquifer 

has moved farther inland than that in the deeper 

Jameco-Magothy aquifer.

FIGURE 7G. Chloride concentration in the upper glacial aquifer in Kings, Queens, and western 

Nassau Counties, N.Y., in 1995-96. 
46 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Atlantic Ocean

East River

Flushing Bay

Flushing Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

MONITORING WELL - number is chloride concentration in mg/L.

PUBLIC – SUPPLY WELL - number is chloride concentration in mg/L.

No data available

Raritan clay unit

. 140

.

ND

R

28

270 310

16000 18000

170

290 500

140

17

6

330 10

37 360

660 640

9

26

77

6400

2300

110 15000

13

6

6

17

49

8

5200

860R

5800

1900

9

76

67

22

200 17

35

29

24

35

12

9

28

58

21

26

ND 12

28

11 23

100

84

22

66

35

31

33

ND

16

10

27

34

6 15

14 14 18

40

8 3

26

35

9

1822

8

11

10

14

.

.

..

.

..

..

. .

.

.

.

.

. .

.

.

.

.

.

.

.

.

. .

. . .

. . .

..

.

. . . .

.

. . .

. . . . .

.. .

.

. .

.

.

.

.

.. ...

. . . . . . .

. .

Lloyd Aquifer

Kings County.—Ground-water-quality data for the 

Lloyd aquifer in Kings County in 1983 are derived 

from only one well (K2859, fig. 9A), because (1) the 

Lloyd aquifer is absent in the northern half of Kings 

County, and (2) potable water is readily obtained from 

shallower wells elsewhere in the county; thus, few deep 

Lloyd aquifer wells have been installed. Well K2859 is 

near the southern shore on Coney Island (fig. 6C) and is 

screened from 466 to 492 ft below sea level. The 1983 

chloride concentration of 52 mg/L at this well indicates 

that the freshwater-saltwater interface was farther 

seaward; Buxton and Shernoff (1995) estimate it to 

have been 1 to 2 mi south of Coney Island.

FIGURE 8A. Chloride concentration in the Jameco-Magothy aquifer in Kings, Queens, and 

western Nassau Counties, N.Y., in 1983. (Modified from Buxton and Shernoff, 1995, fig. 13A.)
Recent (1992-97) Hydrologic Conditions 47

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

. .

.

.

. .

.

.

.

.

. .

.

.

. .

.

..

.

.

MONITORING WELL - number is chloride concentration in mg/L.

PUBLIC – SUPPLY WELL - number is chloride concentration in mg/L.

.180

.

30

16000

140

180

21

6

12

370

40 67

42

3200

2600

140

3

21

130

12000

5000

1600

4

8

14

16

25

18

122

47

16

40 19

15

33

37 30 14

22

41

50

22

240

4

4

350

}

Newto

Cre

wn

ek

Recent (1992 and 1996) data on water quality in 

the Lloyd aquifer in Kings County are derived from 

wells K2859 and K3426, in southern Kings County at 

the border with Queens County (fig. 6F, 6I), and are 

described earlier (figs. 9B, 9C). The chloride 

concentration in 1996 at K2859 is unavailable, but that 

in 1992 was 54 mg/L; this indicates that the 

freshwater-saltwater interface probably has not moved 

since 1983. Well K3426 is a relatively new well 

(installed in 1986) and is screened from about 464 to 

484 ft below sea level. The chloride concentrations at 

this well were 8,200 mg/L (analysis by a private 

laboratory) in 1986, 8,200 mg/L in 1989 (Nassau 

County Department of Public Works [NCDPW] Cedar 

Creek Laboratory), 8,400 mg/L in 1995, and 

8,500 mg/L in 1996. These data suggest that the cone 

of depression in southern Queens County generated by 

public-supply withdrawals from the Lloyd aquifer 

(Buxton and Shernoff, 1995, pl. 6) has caused inland 

migration of saltwater and that the freshwatersaltwater interface may be about 7 mi farther inland 

than previously estimated by Buxton and Shernoff 

FIGURE 8B. Chloride concentration in the Jameco-Magothy aquifer in Kings, Queens, 

and western Nassau Counties, N.Y., in 1992. 
48 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

MONITORING WELL - number is chloride concentration in mg/L.

PUBLIC – SUPPLY WELL - number is chloride concentration in mg/L.

No data available

Estimate based on specific conductance

.300

.

ND

( )

47

.

. . .

.

.

.

.

. .

. . .

.

.

.

.

.

.

.

.

.

.

. .

.

.

.

.

.

. .

.

.

.

.

.

.

.

.

.

16000

47

300

16000

15000

26

ND

4

36

250

13000

ND

5900

1800

3

21

6

460

42 76

46

4700

(2950)

120

65

9

32

12

43

47

20

19

50 32

138

11

8

26

24

58

33

47 17 35

57

16000

4

29

.

(1995). These results are contradicted by analysis of 

data from nearby wells in Queens County, however, as 

discussed further on.

One additional well (K3410, fig. 6I) was 

installed in the Lloyd aquifer during this study. This 

well is in the interior of northeastern Kings County 

and was installed as part of a well doublet; the second 

well at this site is screened in the upper glacial 

aquifer. Well K3410 is screened from 268 to 288 ft 

below sea level with chloride concentrations of 

17 mg/L in 1995 and 1996; these values indicate 

nearly predevelopment quality.

Queens County.—Data on chloride 

concentrations in the Lloyd aquifer in Queens County 

in 1983 are more abundant than those for Kings 

County—the data for Queens County are derived from 

10 monitoring wells and four public-supply wells 

(fig. 9A). Chloride concentrations at inland wells 

FIGURE 8C. Chloride concentration in the Jameco-Magothy aquifer in Kings, Queens, and 

western Nassau Counties, N.Y., in 1996.
Recent (1992-97) Hydrologic Conditions 49

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

MONITORING WELL - number is chloride concentration in mg/L.

PUBLIC – SUPPLY WELL - number is chloride concentration in mg/L.

.14

.

5

52

6

100

10

58

14

1200

8

16

860

5 5

5

5

3

7

. .

.

.

.

.

.

.

.

.

. . .

.

.

ranged from 5 to 18 mg/L, equivalent to 

predevelopment conditions (Buxton and Shernoff, 

1995), but an area near Flushing Bay in northern 

Queens County contained an elevated chloride 

concentration of 1,200 mg/L at Lloyd aquifer well 

Q1373 (and 500 mg/L at upper glacial well Q3134). 

This is the area of the buried channel described by 

Soren (1978), where saltwater has been drawn into the 

Lloyd aquifer laterally or vertically through the upper 

glacial aquifer, which in this area is in hydraulic 

contact with the Lloyd aquifer. Two wells in southern 

Queens County, Q287 on an island in Jamaica Bay, 

and Q1071 on the barrier beach, show chloride 

concentrations of 100 and 58 mg/L, respectively, in 

1983; these concentrations probably indicate the 

landward extent of the freshwater-saltwater interface 

(Buxton and Shernoff, 1995), although the freshwatersaltwater interface is moving landward in this area at 

an estimated rate of 0.02 to 0.05 ft/d (7.3 to 

18.25 ft/yr). The most recent data (discussed below) 

suggest that these concentrations in southern Queens 

County are anomalous, however.

FIGURE 9A. Chloride concentration in the Lloyd aquifer in Kings, Queens, and western 

Nassau Counties, N.Y., in 1983. (Modified from Buxton and Shernoff, 1995, fig. 14A.)
50 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

MONITORING WELL - number is chloride concentration in mg/L.

PUBLIC – SUPPLY WELL - number is chloride concentration in mg/L.

Chloride concentration in1990

.15

.

22

( )

54

6

120

9

56

1100

6

15

22

6

8

8

(10500)

.

.

.

.

.

.

.

.

. . .

.

.

Recent (1992-96) data on ground-water quality in 

the Lloyd aquifer in Queens County are derived from 

four public-supply wells (sampled by JWS in 1992) 

and eight monitoring wells sampled in 1992 and (or) 

1996 (figs. 9B, 9C). Chloride concentrations at inland 

wells (all four public-supply wells and five monitoring 

wells) ranged from 6 to 22 mg/L in 1992, and were 

similar to 1983 values. Chloride concentrations at well 

Q1373 in northern Queens County also were similar to 

those in 1983, ranging from 1,100 mg/L in 1992 to 

1,300 mg/L in 1996. Chloride concentrations at the 

two southernmost wells, Q287 and Q1071, also were 

similar to those of 1983, but the chloride 

concentrations at a new well in southeastern Kings 

County on the Kings/Queens County border (K3426, 

fig. 6I) for 1986, 1989, 1995, and 1996 were 8,200, 

8,200, 8,400, and 8,500 mg/L, respectively.

Figure 9B. Chloride concentration in the Lloyd aquifer in Kings, Queens, and western 

Nassau Counties, N.Y., in 1992
Recent (1992-97) Hydrologic Conditions 51

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

MONITORING WELL - number is chloride concentration in mg/L.

PUBLIC – SUPPLY WELL - number is chloride concentration in mg/L.

Estimate based on specific conductance

.

17

.

5

( )

17

8500

96

7.6

55

1300

(6)

12

15

7 5

5

5

(6)

.

.

.

.

..

.

.

.

.

.

.

.

Samples from new well Q3657 in southern 

Queens County (fig. 6F) were collected by the USGS 

and analyzed by the NCDPW Cedar Creek Laboratory 

in 1989 and 1990; chloride concentrations for these 

years were 10,700 and 10,500 mg/L, respectively. 

These values are considerably higher than those at 

wells Q287 and Q1071, which are 3.75 and 5.5 mi 

farther south, respectively, where higher chloride 

concentrations would be expected. This discrepancy 

also was recognized by Terracciano (1996), who 

suggested that additional data would be necessary for 

a proper assessment. These data suggest that either (1) 

chloride values for the two older, southern wells 

(Q287 and Q1071) or those for the two newer, 

northern wells could be in error, or (2) the data from 

all four wells are correct and indicate that an 

unidentified hydrologic or chemical process is 

occurring. The validity of data from the older wells 

FIGURE 9C. Chloride concentration in the Lloyd aquifer in Kings, Queens, and western 

Nassau Counties, N.Y., in 1996.
52 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

would be easiest to dismiss because of the age of the 

wells, and because vandals had repeatedly dropped 

debris into well Q287 until 1956, by which time it was 

completely full and not usable. The USGS prepared a 

plan in 1956 to remove the debris, but whether the 

work was performed is unknown. Similarly, wellconstruction data for well Q1071 are sparse—three 

casing sizes are reported to have been used, but no 

information on the length of each has been found. 

Therefore, estimates of casing length must be used to 

calculate casing volumes for well purging before 

sampling. Also, because the estimated casing volumes 

were large, only two casing volumes were removed 

prior to sampling in 1983 and 1996. Either factor 

could have resulted in the collection of a water sample 

unrepresentative of local ground-water conditions. In 

addition, water in the upper glacial and Magothy 

aquifers in the vicinity of the two old, southern wells 

Q287 and Q1071 is saline; thus, if their casings are no 

longer sound and allow water to leak from overlying 

aquifers, only saline water would leak into the well. 

Therefore, the relatively fresh water obtained from 

these wells is probably from the Lloyd aquifer, an 

indication that the low chloride values are valid and 

that saltwater has not moved this far inland.

In contrast to the questionable well-completion 

data of Q287 and Q1071, well-completion data for the 

newer wells K3426 and Q3657 indicate grouting of 

the annular space through the Raritan clay and backfill 

to land surface; this probably eliminates seepage from 

the overlying Magothy aquifer as a source of saltwater 

contamination. The large cone of depression and head 

distribution in the Lloyd aquifer (Buxton and 

Shernoff, 1995, pl. 6 and 7, respectively), both of 

which indicate landward movement of the freshwatersaltwater interface in this aquifer, also support the 

validity of the elevated chloride concentrations at 

K3426 and Q3657. Nevertheless, installation of new 

deep (Lloyd aquifer) wells near the older wells and in 

bordering areas are needed to (1) help assess the 

integrity of data from older wells, (2) discover any 

hydrogeologic anomalies, and (3) define the inland 

extent of saltwater in southern Queens County.

Nitrate

Predevelopment nitrate concentrations in ground 

water on Long Island probably were less than 

0.2 mg/L as N (Buxton and Shernoff, 1995). Nitrogen, 

in the form of nitrate, typically is introduced into 

ground-water systems from fertilizers and domestic 

waste dissolved in recharge. Nitrate also enters the 

ground-water system in Kings and Queens Counties 

through leakage from New York City’s combinedsewer network (Kimmel, 1972). 

The following sections discuss the concentrations 

of nitrate in water from the three major aquifers 

underlying Kings, Queens, and western Nassau 

Counties in 1983, 1992, and 1996.

Upper Glacial Aquifer

Concentration in 1983.—Nitrate contamination 

of the upper glacial aquifer in Kings County in 1983 

was widespread (fig. 10A). Nitrate concentrations, in 

mg/L (as N), at 35 monitoring wells ranged from 

0.29 mg/L to 20 mg/L. Concentrations in 19 of the 35 

wells exceeded the New York State public-health 

standard of 10 mg/L. In Queens County, nitrate 

concentrations in 24 of 39 wells exceeded 5 mg/L, and 

in 8 of the 39 wells they exceeded the public-health 

standard. The range in nitrate concentrations 

(0.2 mg/L to 22 mg/L) in Queens County is similar to 

that in Kings County. Nitrate concentrations 

mentioned above are from Buxton and Shernoff (1995) 

and probably decrease eastward and with depth. 

Concentrations in 1992 and 1996.—Recent 

(1992 and 1996) nitrate concentrations are reported as 

dissolved nitrate plus nitrite (figs. 10B, 10C); whereas 

those for 1983 were reported as total nitrate. The 

values for these two sampling periods are comparable, 

however, because: (1) nitrite concentrations typically 

represent only a negligible fraction of the nitrate 

concentrations and can, therefore, be ignored, and (2) 

the percentage of colloidal (undissolved) nitrite plus 

nitrate in ground water is negligible in relation to the 

dissolved fraction. Concentrations at 26 monitoring 

wells in Kings County in 1996 ranged from less than 

0.05 to 17 mg/L. Nitrate concentrations at 23 wells 

that were sampled in 1983 and 1996 are available; of 

these 23 wells, 13 showed a decrease in nitrate 

concentration during this period, 4 wells showed no 

change, and 6 wells showed an increase. Similar 

results are seen in Queens County data. Nitrate 

concentrations at 25 of 31 wells sampled in 1996 in 

Queens County ranged from less than 0.05 to 13 mg/l. 

Nitrate concentrations at 12 wells that were sampled in 

1983 and 1996 are available; of these 12 wells, 11 

wells showed a decrease, and only 1 well showed an 

increase. Additional nitrate data from 9 monitoring 

wells sampled in 1996 but not in 1983 are available. 

Of these, 7 samples showed concentrations below the 
Recent (1992-97) Hydrologic Conditions 53

public health standard of 10 mg/L. Nitrate 

concentrations for Nassau County are available for 4 

wells sampled in 1983 and 1992 and (or) 1996. All 

values were well below 10 mg/L and did not change 

significantly during this period.

Nitrate concentrations at seven public-supply 

wells in Queens County in 1996 are available. All 

concentrations were below 10 mg/L and ranged from 

3.9 to 7.3 mg/L (analyses performed by former JWS). 

Five of these wells were sampled in 1983; the 

concentrations had decreased in two wells and 

increased in three wells, apparently in opposition to 

the decreasing trends described earlier for all 

monitoring wells. These nitrate concentrations are low, 

however, and the small changes from 1983 to 1996 

may not be significant.

The majority of nitrate concentrations measured 

in the upper glacial aquifer in Kings, Queens, and 

western Nassau Counties in 1992 and 1996 were lower 

than in 1983. This observation is consistent with the 

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

MONITORING WELL - number is nitrate concentration in mg/L.

PUBLIC – SUPPLY WELL - number is nitrate concentration in mg/L.

No Data Available

. 3.5

. 4.2

.

.

. . . . .

.

.

. . .

.

.

.

.

.

.

.

. .

. .

.

. .

. .

. . .

.

. .

.

.

. .

.

.

.

. .

..

.

.

.

.

.

.

.

. . .

.

. .

.

.

.

. ..

.

. .

.

. .

.

.

. .

. . .

.

.

. . .

.

.. .

. .

.

.

ND

.

4.6

0.29

5.2

13

7.5

0.8

>10

9.2

4

14

8.9

>10

>10

>10

>10

>10

0.85 >10

>10

13

10

0.8

0.4

8.6

7.8

0.2

5.8

ND

0.3

7 17

>10

3.5

>10

9.2

6.4

11

1.9

20

18

16 ND

>10

9.2

22 0.36 ND

4.8

0.27

ND ND 0.5

0.24

ND >10 2.1

2.8

11

11

ND

6.2

7.6

5.4

11

7.8

3.4

5.3

8.8

ND

5.2

8.2

1.1

10 4.2

8.2

7.6 10

7.2

8.8

5.6

4.1

3.7

6.4

1.2

0.03

6.4

12

8.6

0.09

2.3

6.7

4.4

FIGURE 10A. Nitrate concentration in the upper glacial aquifer in Kings, Queens, and 

western Nassau Counties, N.Y., in 1983. (Modified from Buxton and Shernoff, 1995, fig. 12B.)
54 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

decrease in chloride concentrations described earlier 

and can be attributed to the same mechanism of 

dispersion, degradation, and (or) dilution resulting 

from the long-term water-level recovery as well as 

denitrification.

Jameco-Magothy Aquifer

Nitrate concentrations at six wells screened in the 

Jameco-Magothy aquifer in Kings County in 1983 are 

depicted in figure 11A (Buxton and Shernoff, 1995) 

and range from 0.24 to greater than 10 mg/L. These 

concentrations generally are higher than those in 

Queens and western Nassau Counties, where the 

Gardiners Clay is present, and are attributed to a 

greater vertical hydraulic conductivity of this unit in 

Kings County than in Queens and Nassau Counties. 

This high hydraulic conductivity allows rapid 

movement of nitrate-contaminated water to the 

Jameco-Magothy aquifer.

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

MONITORING WELL - number is nitrate concentration in mg/L.

PUBLIC – SUPPLY WELL - number is nitrate concentration in mg/L.

.4.7

.

5.3

8.7

9.6

7.6

5.3

5.3

6.6

8.2

5.7

2.9

8.4

9.4

11

9.7

4

16

7.5

16

<0.05

6.3

8

8.3 5

12

10

6.6

14

9.9

6.7

7.2

4.7

<0.05

4.7

9.6

<0.05

11

5.7

<0.05

<0.05

6.5

9.1

<0.05

<0.05

<0.05

<0.05

<0.05

3.8 3.1

<0.05

0.01 2

<0.05

<0.05

6.8

22.9

1

12 3.5 0.6 6.7

7.2

6.3

<0.1

5.2

 3 9.9

4.5

7.9

6.3

<0.1

6.2

8.8

10.1

5.3

5.4

5.9 10.6

7.6

6.4

9.2

9.4

<0.05

3.3

10.1

7.8

.

. .

. .

. .

.

. . . .

.

.

.

.

.

.

.

.

.

.

.

. .

. .

.

.

.

. .

.

.

.

. .

.

.

.

. .

.

.

.

. .

.

. . .

.

.

. ..

.

. .

.

.

.

. . .

. .

.

.

.

. .

.

.

.

. ..

.

.

.

FIGURE 10B. Nitrate concentration in the upper glacial aquifer in Kings, Queens, and western 

Nassau Counties, N.Y., in 1992. 
Recent (1992-97) Hydrologic Conditions 55

Nitrate concentrations at 10 of 12 JamecoMagothy aquifer wells sampled in 1983 in parts of 

southern Queens and Nassau Counties, where the 

Gardiners Clay is present, were 0.28 mg/L or less. The 

highest nitrate concentration among these 12 wells 

was 0.79 mg/L. In contrast, the 1983 nitrate 

concentrations at 34 of 47 inland wells, where the 

Gardiners Clay is absent, exceeded 2 mg/L. These data 

reflect the effect of the Gardiners Clay on nitrate 

concentration, as described earlier.

Recent (1992 and 1996) nitrate concentrations in 

the Jameco-Magothy aquifer at seven monitoring 

wells in Kings County are available (figs. 11B, 11C); 

concentrations range from less than 0.05 to 8.5 mg/L. 

Nitrate concentrations at two wells sampled in 1996 

showed an increase from 1983. Concentrations at nine 

monitoring wells in Queens County in 1996 ranged 

from less than 0.05 to 5.9 mg/L; those at five of six 

wells sampled in 1983 were lower in 1996, and that at 

one was higher. Similar trends are observed in western 

Nassau County—recent (1996) nitrate concentrations 

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

MONITORING WELL - number is nitrate concentration in mg/L.

PUBLIC – SUPPLY WELL - number is nitrate concentration in mg/L.

No Data Available

.8.5

.

5.1

.

. .

. .

. .

.

.

. .

.

. .

. .

.

.

. .

. . .

. .

. .

.

.

.

.

.

.

. . . .

.

.

. .

.

..

. .

.

.

.

.

. .

.

.

.

.

.

.

.

.

.

. .

.

.

. .

..

.

3

8.9

7.7

6

5.3

2.5

6.1

4.6

0.4

5

10 11

8.7

17

3.1

<0.05

6.2

12

10 11

16

6

8.5

4.2

ND

6.3

5.2 0.2

ND

0.03

10

<0.05

ND

5.5

0.06

5.6

5.6

6

<0.05

.07

<0.05 .07

<0.05

<0.05

4.7

.07

3.6

ND

13 <0.05

11

ND

4.5

ND

4.2

ND

6.9

3.5

2.8

1.5

4.9 4.3 6.7

7.3

5.9

5.2

3.9

6.4

5.1

<0.05

ND

2.9

ND

FIGURE 10C. Nitrate concentration in the upper glacial aquifer in Kings, Queens, and 

western Nassau Counties, N.Y., in 1996.
56 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

at nine monitoring wells ranged from less than 0.05 to 

0.54 mg/L. All of these wells were sampled in 1983; 

the nitrate concentration at four wells had decreased 

by 1996, at three wells it had increased, and at two 

wells it remained constant. 

Nitrate concentrations for 1996 at an additional 

17 JWS wells screened in the Jameco-Magothy 

aquifer in Queens County are available. These publicsupply wells are in central and eastern parts of the 

county, and the nitrate concentrations in 1996 ranged 

from less than 0.1 to 8 mg/L. These values, although 

less than 10 mg/L, generally are higher than those at 

Jameco-Magothy aquifer wells farther south, where 

the Gardiners Clay is present. Nitrogen concentrations 

at all 17 wells for 1983 and 1996 are available. A 

comparison of these data indicates that nitrate 

concentration decreased at seven wells, increased at 

three wells, and remained constant at seven wells. 

JWS provided 1996 data for 14 Jameco-Magothy 

aquifer wells in Nassau County; there the nitrate 

concentrations ranged from less than 0.1 to 7.2 mg/L. 

Concentrations at 13 of these public-supply wells in 

1983 are available for comparison. The concentration 

Atlantic Ocean

East River

Flushing Bay

Flushing Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

MONITORING WELL - number is nitrate concentration in mg/L.

PUBLIC – SUPPLY WELL - number is nitrate concentration in mg/L.

No Data Available

.1.4

.

0.7

ND

6

14

ND

>10

0.24

1.4

ND

1.6

0.79

>10

6.9 7.8

0.23

8.2

0.4

<0.01

ND

0.05

0.03

0.07

0.09

0.28

0.07

0.25

0.17

0.4

<0.1

<0.1

6.2

0.2

5.9

4.2

7.2

3.4

6.1

<0.1

3.4

<0.1

6.8

3.6

6.0 ND

0.7

2.5 9.8

4.0

4.2

3.2

4.2

<0.1

5.2

0.1 <0.1

0.4 0.1

4.2

<0.1

3.6 2.5

1.7

<0.1

3.6

4.6

ND

ND

9.5

2.8

ND

0.4

6.6

2.6

6.2

<0.1

1.2

3.0

2.0

5.8

3.4

6

ND

5.8

1.3

1.4

{

}

{

{

{

.

.

..

. .

.

.

.. .

. .

.

.

. .

.

.

.

.

.

.

. .

. .

.

.

. .

.

.

.

.. .

. . .

.

. .

.

.

.

. .

.

. . .

.

.

.

.

..

. .

.

.

. .

.

.

. ..

.

.

.

.

FIGURE 11A. Nitrate concentration in the Jameco-Magothy aquifer in Kings, Queens, and 

western Nassau Counties, N.Y., in 1983. (Modified from Buxton and Shernoff, 1995, fig. 13B.)
Recent (1992-97) Hydrologic Conditions 57

at five wells decreased; at six wells they remained 

constant, and at two wells they increased.

Lloyd Aquifer

Nitrate data from 14 wells screened in the Lloyd 

aquifer in 1983 are available (fig. 12A) (Buxton and 

Shernoff, 1995). The 1983 concentrations ranged from 

less than 0.1 to 0.72 mg/L, indicating little or no 

contamination from land surface, despite (1) the 

hydraulic connection provided by the buried channel 

in central Queens County, and (2) the increased 

downward gradients produced by progressively 

greater public-supply withdrawals from the Lloyd 

aquifer in southeastern Queens from about 3 Mgal/d to 

6 Mgal/d since 1960. Traveltimes of ground water 

through the buried channel and into the Lloyd aquifer 

probably would be decades, whereas the traveltime for 

movement through the Raritan clay into the Lloyd 

aquifer would probably be millennia (Buxton and 

Shernoff, 1995).

Recent (1992 and 1996) water-quality data from 

19 observation and public-supply wells screened in the 

Lloyd aquifer in Kings, Queens, and western Nassau 

Counties are available (figs. 12B, 12C). Nitrate 

concentrations at 18 wells ranged from less than 0.05 

.

<0.05

.

.

. .

.

.

.

. . .

.

.

.

. .

.

..

. . .

. . . .

. .

.

.

.

. .

.

..

..

.

.

.

.

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

MONITORING WELL - number is nitrate concentration in mg/L.

PUBLIC – SUPPLY WELL - number is nitrate concentration in mg/L.

.12

1.3

<0.05

.12

2.6 4.4

<0.05

3.7 7.2

2.3

<0.05

<0.05

<0.05

.07

<0.05

<0.05

<0.05

<0.05

<0.1

6.7

0.2

<0.1

4.1

6.7

7.6

1.5

6

3

<0.1

<0.1

4.3

3.2

3.5 3.9

5.1

<0.1

<0.1 <0.1

1.6

6.7

1.9

<0.1

1.3

<0.1

0.8

4.6

<0.1

4.6

1.1 6.8

9.2 4.2

7.8

0.2

0.4

7.7 8.6

12.2 5.7 2.8 4.7

0.4

7.9

<0.05

<0.05

<0.05

3.3 6.8

6.9

8.1

{

{ }

{

.

.

.

.

.

.

. .

.

.

.

.

.

.

.

.

. .

.

.

<0.05

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

FIGURE 11B. Nitrate concentration in the Jameco-Magothy aquifer in Kings, Queens, and 

western Nassau Counties, N.Y., in 1992. 
58 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

to 1.6 mg/L, indicating little or no contamination from 

land surface; the concentration at a single publicsupply well was slightly elevated above background 

levels (6.6 mg/L) but below the public health standard. 

Nitrate data for 1992 and (or) 1996 are available for 7 

of the 19 wells sampled in 1983; nitrate concentrations 

at all 7 wells decreased during this period, indicating 

that (1) 1983 concentrations were slightly elevated, 

probably by minor contamination from the surface, 

and (2) the water quality in terms of chloride 

concentration is improving.

Organic Compounds

Prior to 1983, no comprehensive ground-water 

sampling had been undertaken in Kings or Queens 

Counties to document the presence of organic 

compounds (Buxton and Shernoff, 1995). In 1979, 

however, JWS (under the auspices of the New York 

City Department of Health, NYCDH) began analyzing 

ground water from public-supply wells in Queens and 

western Nassau Counties for total volatile organic 

compounds (VOC’s). In 1983, 42 of 54 JWS wells 

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

MONITORING WELL - number is nitrate concentration in mg/L.

PUBLIC – SUPPLY WELL - number is nitrate concentration in mg/L.

No Data Available

. 8.5

. 1.3

.1

8.5

.07

.06

<.05

<.05

ND

.08

.19

.07

<.05

.08

ND

.06

.54

<.05

3.8

2.6

ND

3.7 5.98

2.4

<.05

<.05

<.05

<.05

5.8

0.1

5.9

7.2

6

2.1

3

<0.1

4

2.6

2.3 2.9

4.2

<0.1 <0.1 <0.1

1.3

0.1

0.4

4.2

3.6

0.4 8

5.5

2.5 3.7 7.6

.09

2.9

5.2

3.6

. .

.

.

.

.

.

. .

.

.

.

.

.

.

.

. .

. .

. . .

.

..

.

. . .

.

.

. .

.

.

. .

. .

.

.

.. ..

.

.

.

ND

FIGURE 11C. Nitrate concentration in the Jameco-Magothy aquifer in Kings, Queens, and 

western Nassau Counties, N.Y., in 1996.
Recent (1992-97) Hydrologic Conditions 59

sampled showed detectable concentrations of total 

VOC’s (detection limit 0.1 μg/L); and the VOC 

concentration in two of these exceeded recommended 

guidelines set by NYCDH. Most of the contamination 

was in the upper glacial and Magothy aquifers (where 

most of the pumping occurs), 22 of 23 upper glacial 

aquifer wells, 19 of 27 Jameco-Magothy aquifer wells, 

and one of four Lloyd aquifer wells showed detectable 

VOC concentrations (Stern and Todd, 1984). The 

contamination in southeastern Queens County was 

attributed to migration from scattered point sources 

near the surface, through the upper glacial aquifer, and 

into the Jameco-Magothy aquifer (Buxton and 

Shernoff, 1995).

Public-Supply Wells

Concentrations of organic compounds (VOC’s 

and pesticides) in public-supply wells in 1992 and 

1996 presented here are from JWS records. Only those 

concentrations that exceed their respective detection 

limits are reported here. When organic compounds are 

detected in a JWS well, either (1) water from the well 

is blended with uncontaminated water from another 

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

MONITORING WELL - number is nitrate concentration in mg/L.

PUBLIC – SUPPLY WELL - number is nitrate concentration in mg/L.

No Data Available

. 3.7

. 0.1

0.24

0.12

0.72

2.7

ND

3.7

0.14

0.2

ND

1.4

0.1 <0.1

<0.1

<0.1

<0.1

0.16

. .

.

.

.

.

.

.

.

.

. . .

.

.

ND

FIGURE 12A. Nitrate concentration in the Lloyd aquifer in Kings, Queens, and western Nassau 

Counties, N.Y., in 1983. (Modified from Buxton and Shernoff, 1995, fig. 14B.)
60 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

well to lower the concentrations to allowable levels, or 

(2) the well is taken offline and no longer routinely 

sampled. Results of blended-water analyses are not 

reported here because they are not representative of 

the water quality at a single site. For these reasons, the 

data presented here indicate water quality at publicsupply wells where detection limits have been 

exceeded and are not representative of the water 

quality in the entire Jamaica area of Queens County.

The locations of public-supply wells in the 

Jamaica area of Queens County (including western 

Nassau County) at which organic constituents were 

detected in 1992 are presented in figure 13A (upper 

glacial aquifer) and 13B (Magothy and Lloyd 

aquifers); locations of those wells affected in 1996 are 

shown in figure 14A (upper glacial aquifer) and 14B 

(Jameco-Magothy aquifer). The corresponding waterquality data are presented in table 5 (Queens County, 

1992), table 6 (Nassau County, 1992), table 7 (Queens 

County, 1996), and table 8 (Nassau County, 1996).

1992 - Queens County.—Detectable 

concentrations of organic compounds were present in 

39 public-supply wells in Queens County in 1992; 19 

wells were screened in the upper glacial aquifer, 19 in 

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

MONITORING WELL - number is nitrate concentration in mg/L.

PUBLIC – SUPPLY WELL - number is nitrate concentration in mg/L.

.0.04

.

1.3

<0.05

<0.05

<0.05

1.6

<0.05

0.04

<0.05

<0.05

<0.1

1.3

<0.1

<0.1 <0.1

<0.05

. .

.

.

.

.

.

.

. . .

.

.

FIGURE 12B. Nitrate concentration in the Lloyd aquifer in Kings, Queens, and western Nassau 

Counties, N.Y., in 1992.
Recent (1992-97) Hydrologic Conditions 61

the Jameco-Magothy aquifer, and 1 in the Lloyd 

aquifer (figs. 13A, 13B; table 5). The most frequently 

detected compounds were tetrachloroethene (28 

wells), chloroform (16 wells), total trihalomethanes 

(14 wells), and trichloroethene (13 wells). Other 

individual organic compounds were present in less 

than 20 percent of the 39 wells (7 wells) at which 

organic compounds were detected. 

Tetrachloroethene detections were distributed 

evenly between the upper glacial and JamecoMagothy aquifers—in 14 of the 19 upper glacial 

aquifer wells, and in 14 of the 19 Jameco-Magothy 

aquifer wells. Chloroform was detected most 

frequently in samples from upper glacial aquifer 

wells—in 10 of the 19 upper glacial aquifer wells, in 5 

of the 19 Jameco-Magothy aquifer wells, and in the 1 

Lloyd aquifer well. Total trihalomethanes also were 

detected most frequently in samples from upper 

glacial aquifer wells—in 9 of the 19 upper glacial 

aquifer wells, in 4 of the 19 Jameco-Magothy aquifer 

wells, and in the Lloyd aquifer well. trichloroethene 

detection in upper glacial aquifer wells was similar to 

that in Jameco-Magothy aquifer wells—in 6 of the 19 

upper glacial aquifer wells, and in 7 of the JamecoAtlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

MONITORING WELL - number is nitrate concentration in mg/L.

PUBLIC – SUPPLY WELL - number is nitrate concentration in mg/L.

No Data Available

.13

. 6.6

13

.04

.05

ND

ND

ND

<0.05

<0.05

<0.05

.06

.24

<0.1

<0.1

6.6

.45

.

.

.

.

.

.

.

.

.

.

.

.

.

ND

FIGURE 12C. Nitrate concentration in the Lloyd aquifer in Kings, Queens, and western 

Nassau Counties, N.Y., in 1996.
62 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Magothy aquifer wells. Concentrations of organic 

compounds ranged from 0.5 μg/L to 150 μg/L; 

tetrachloroethene had the highest concentration 

(150 μg/L), and total trihalomethanes the next-highest 

concentration (37 μg/L).

1992 - Nassau County—Detectable 

concentrations of organic compounds were present in 

16 public-supply wells in Nassau County in 1992; 4 

wells were upper glacial aquifer wells, and 12 were 

Jameco-Magothy aquifer wells (figs. 13A, 13B; 

table 6). The most frequently detected compounds 

were tetrachloroethene (12 wells), trichloroethene (9 

wells), chloroform (5 wells), and total trihalomethanes 

(5 wells). Other organic compounds were detected in 3 

or less of the 16 wells at which organic compounds 

were detected. Tetrachloroethene was detected in 2 of 

the 4 upper glacial aquifer wells and in 10 of the 12 

Jameco-Magothy aquifer wells. Similarly, 

trichloroethene was detected in 2 of the 4 upper glacial 

aquifer wells, and in 7 of the 12 Jameco-Magothy 

aquifer wells. Chloroform and total trihalomethanes, 

in contrast, were detected in 3 of the 4 upper glacial 

aquifer wells, but in only 2 of the 12 Jameco-Magothy 

aquifer wells. Organic compound concentrations 

ranged from 0.5 μg/L to 160 μg/L. Trichloroethene 

had the highest concentration (160 μg/L), 1,2-

Flushing Bay

Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

Jamaica Bay

73°45'

0 1 2 3 4 5 MILES

0 1 2 3 4 5 KILOMETERS

40o48'

EXPLANATION

 Public – supply well and

.

 NYSDEC well identifier

Q1747

Q1843

Q1997

Q2001

Q2138

Q2189

Q2275 Q2299

Q2321

Q2442

Q301

Q303

Q305

Q310

Q313

Q321

Q322

Q323

N14

N4077

N6744 N5155

.

.

.

.

.

.

. . .

. .

.

.

. . .

..

..

.

.

Q322

FIGURE 13A. Locations of public-supply wells screened in the upper 

glacial aquifer in Queens and western Nassau Counties, N.Y., at which 

volatile organic compounds were detected in 1992.
Recent (1992-97) Hydrologic Conditions 63

dichloropropane had the second highest (150 μg/L), 

and tetrachloroethene had the third highest (25 μg/L).

1996 - Queens County—Detectable 

concentrations of organic compounds were present in 

19 public-supply wells in Queens County in 1996; 7 

wells were screened in the upper glacial aquifer, and 

12 in the Jameco-Magothy aquifer (figs. 14A, 14B; 

table 7). The most frequently detected compounds 

were tetrachloroethene at 17 of the wells, and 

trichloroethene at 7 of the wells. Other individual 

organic compounds were detected in 4 or less of the 19 

wells. Tetrachloroethene detections were distributed 

roughly equally between the two aquifers, with 

detections in 6 of the 7 upper glacial aquifer wells, and 

11 of the 12 Jameco-Magothy aquifer wells. 

trichloroethene was detected at 5 of the 12 wells in the 

Jameco-Magothy aquifer and at 2 of the 7 wells in the 

upper glacial aquifer. Organic compound 

concentrations in both aquifers ranged from 0.5 μg/L 

to 220 μg/L. Tetrachloroethene had the highest 

concentrations (220, 79, 54, and 24 μg/L); 

trichloroethene had the next highest concentration 

(34 μg/L).

1996 - Nassau County—Detectable 

concentrations of organic compounds were present in 

10 public-supply wells in western Nassau County in 

Flushing Bay

Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

Jamaica Bay

73°45'

0 1 2 3 4 5 MILES

0 1 2 3 4 5 KILOMETERS

40o48'

EXPLANATION

. .

.

.

.

. .

. .

.

.

. .

.

.

.

. .

.

.. .

.

. .

.

.

Q1600

Q1629

Q1815

Q1957

Q2000

Q2027 Q2276

Q2300

Q2332

Q2362

Q2363

Q2374

Q2409

Q2432

Q2435

Q3014

Q566

N11

N17

N3720

N4298

N4390

N4512

N5156 N6745

N7445

N7649

N7650

N11037

Q317 (Lloyd) Q2028

Q2373

Q2408

Q2332 Public – supply well and

.

 NYSDEC well identifier

(Lloyd) Well screened in Lloyd Aquifer

FIGURE 13B. Locations of public-supply wells screened in the JamecoMagothy or Lloyd aquifers in Queens and western Nassau Counties, 

N.Y., at which volatile organic compounds were detected in 1992.
64 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

1996; 2 wells were screened in the upper glacial 

aquifer, and 8 in the Jameco-Magothy aquifer 

(figs. 14A, 14B; table 8). The most frequently detected 

compounds were tetrachloroethene (8 of the 10 wells), 

and trichloroethene (6 of the wells). Other organic 

compounds were detected at 3 or less of the 10 wells. 

Tetrachloroethene was detected at seven of the eight 

Jameco-Magothy aquifer wells and at one of the two 

upper glacial aquifer wells. Trichloroethene was 

detected at five of the eight Jameco-Magothy aquifer 

wells and at one of the two upper glacial aquifer wells. 

Organic compound concentrations ranged from 

0.06 μg/L (dieldrin) to 170 μg/L (trichloroethene). 

Trichloroethene had the highest concentrations (170, 

22, and 21 μg/L); and tetrachloroethene the next 

highest (16 μg/L).

Monitoring Wells

Concentrations of organic compounds, including 

VOC’s and pesticides, also were measured in water 

from monitoring wells. Data from the USGS 1992-93 

and 1995 sampling periods are available for wells in 

Kings, Queens, and western Nassau Counties; data 

from the 1996 sampling period are available from the 

NYCDEP. Locations of wells at which at least one 

organic compound was detected are shown in 

figure 15; the data associated with these wells are 

summarized in table 9.

Flushing Bay

Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

Jamaica Bay

73°45'

0 1 2 3 4 5 MILES

0 1 2 3 4 5 KILOMETERS

40o48'

EXPLANATION

.

. .

.

. .

.

.

.

.

Q1997

Q2189

Q305

Q310

Q313

Q321

N17

N4390

N5155

Q1747

 Public – supply well and

.

 NYSDEC well identifier

Q2189

FIGURE 14A. Locations of public-supply wells screened in the upper 

glacial aquifer in Queens and western Nassau Counties, N.Y., at which 

volatile organic compounds were detected in 1996.
Recent (1992-97) Hydrologic Conditions 65

Ground water collected during the 1992-93 and 

1995 sampling periods from 108 wells in Kings, 

Queens, and western Nassau Counties was analyzed 

for organic compounds. Of these wells, 26 had 

detectable concentrations of at least one organic 

compound. The number of organic compound 

detections in Kings County is twice the number in 

Queens County—16 of the 43 wells in Kings County 

had detectable concentrations, in contrast to only 9 of 

the 50 wells in Queens County, and only 1 of the 15 

wells in Nassau County. Again, the most commonly 

detected organic compounds were tetrachloroethene 

(12 detections) and trichloroethene (9 detections), 

followed by chloroform (5 detections). Maximum 

concentrations were similar to those in public-supply 

wells and ranged from 0.02 μg/L for p,p ́-DDT and 

2,4-D (pesticides) to 150 μg/L for tetrachloroethene. A 

single value of 1,000 μg/L was reported for tert-butyl 

methyl ether.

The distribution of organic compounds among 

the aquifers at monitoring wells in Kings County is 

substantially different from those at public-supply 

wells in Queens County. All Kings County wells with 

detectable concentrations of organic compounds were 

screened in the upper glacial aquifer, as were seven of 

the eight Queens County wells (the other one was 

Flushing Bay

Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

Jamaica Bay

73°45'

0 1 2 3 4 5 MILES

0 1 2 3 4 5 KILOMETERS

40o48'

EXPLANATION

 Public – supply well and

.

 NYSDEC well identifier

Q2332

.

..

.

. .

.

. .

.

.

. ..

.

.

.

.

Q1957

Q1958

Q2276 Q2300

Q2332

Q2373

Q2374

Q2408

Q2432

Q2435

Q3014

N10207

N17

N3720

N4298

N4390

N6745 N5156

N7649

N7650

Q2409

Figure 14B. Locations of public-supply wells screened in the JamecoMagothy aquifer in Queens and western Nassau Counties, N.Y., at which 

volatile organic compounds and one pesticide were detected in 1996
66 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Table 5. Concentrations of selected volatile organic compounds in water from publicsupply wells in Queens County, N.Y., 1992

[Well locations are shown in fig. 13A and 13B. Concentrations are in micrograms per liter (μg/L). Detection limits 

for all compounds is 0.5 μg/L. NYSDEC, New York State Department of Environmental Conservation. JWS, 

Jamaica Water Supply Company]

Well number

Aquifer

Sampling

NYSDEC JWS date Constituent Concentration

Q1600 13-A Magothy 11/19/92 Tetrachloroethene 1.8

Q1629 29-A Magothy 9/11/92 Trichloroethene 1.1

12/2/92 Trichloroethene 1

Q1747 27 Upper glacial 5/11/92 1,2,4-Trimethylbenzene 0.6

1,2-Xylene 2.1

1,3-Xylene 2.9

Bromodichloromethane 7.9

Bromoform 7.7

Chlorodibromomethane 9.4

Chloroform 12

Ethylbenzene 1.3

Isopropylbenzene (cumene) 0.7

Naphthalene 1.7

Total trihalomethanes 37

10/28/92 Tetrachloroethene 0.5

Q1815 26-A Magothy 2/3/92 Dichlorodifluoromethane 8.1

Tetrachloroethene 12

Q1843 33 Upper glacial 12/4/92 Chloroform 1.7

Tetrachloroethene 1.7

Total trihalomethanes 1.7

Trichloroethene 0.5

Q1957 5-A Magothy 10/15/92 Dichlorodifluoromethane 2.8

Tetrachloroethene 9.7

12/10/92 Tetrachloroethene 14

Trichloroethene 0.6

1/13/92 Trichloroethene 0.6

Q1997 38 Upper glacial 10/15/92 Benzene 0.6

12/10/92 1,1,1-Trichloroethane 1.4

Tetrachloroethene 6.4

Trichloroethene 0.6

1/13/92 cis-1,2-Dichloroethene 0.6

Q2000 39 Upper glacial 3/16/92 Chloroform 1.1

Tetrachloroethene 8.1

Total trihalomethanes 1.1

Q2001 37 Upper glacial 11/24/92 Tetrachloroethene 0.9

Q2027 42 Upper glacial 3/16/92 Chloroform 1.3

Total trihalomethanes 1.3

Q2028 42 Magothy 3/20/92 Trichloroethene 0.5

Q2138 43 Upper glacial 7/29/92 1,1,1-Trichloroethane 0.6

12/11/92 Tetrachloroethene 7.7

Trichloroethene 4.2

Q2189 5 Upper glacial 11/19/92 Tetrachloroethene 0.9

Q2275 47 Upper glacial 9/14/92 Tetrachloroethene 0.5

 12/2/92 Chloroform 0.8

Total trihalomethanes 0.8

Q2276 47-A Magothy 4/27/92 Chloroform 0.6

Total trihalomethanes 0.6

1/22/92 Chloroform 1.6

Total trihalomethanes 1.6

Q2299 48 Upper glacial 4/16/92 Total trihalomethanes 0.6
 Recent (1992-97) Hydrologic Conditions 67

Chloroform 0.6

1,2,3-Trichloropropane 0.7

11/12/92 1,2,3-Trichloropropane 0.5

12/10/92 Tetrachloroethene 31

Trichloroethene 1.4

Q2300 48-A Magothy 1/13/92 1,1,1-Trichloroethane 0.5

2/14/92 1,1,1-Trichloroethane 0.5

11/12/92 cis-1,2-Dichloroethene 1.3

Tetrachloroethene 140

Trichloroethene 16

12/10/92 cis-1,2-Dichloroethene 1.4

Tetrachloroethene 150

Trichloroethene 19

Q2321 49 Upper glacial 4/27/92 Chloroform 0.8

Total trihalomethanes 0.8

Q2332 43-A Jameco 3/30/92 1,2-Xylene 1.8

1,3-Xylene 2.6

Chloroform 1.4

Ethylbenzene 0.8

Tetrachloroethene 2.5

Total trihalomethanes 1.4

11/18/92 Tetrachloroethene 2.8

Trichloroethene 0.9

Q2362 51 Magothy 2/3/92 Tetrachloroethene 11

Q2363 52 Magothy 2/13/92 1,1,1-Trichloroethane 0.8

Tetrachloroethene 8.7

Q2373 50 Magothy 12/17/92 Tetrachloroethene 24

Q2374 50-A Magothy 11/12/92 Tetrachloroethene 10

12/17/92 Tetrachloroethene 9.7

Q2408 53 Magothy 9/9/92 Chloroform 0.5

12/10/92 1,1,1-Trichloroethane 0.6

Tetrachloroethene 22

Q2409 53-A Magothy 11/12/92 Tetrachloroethene 6.9

12/10/92 Tetrachloroethene 7.1

Q2432 38-A Magothy 11/12/92 1,1,1-Trichloroethane 2.7

1,1-Dichloroethane 0.8

1,1-Dichloroethene 1.2

cis-1,2-Dichloroethene 30

Tetrachloroethene 110

Trichloroethene 13

12/10/92 1,1,1-Trichloroethane 3.5

1,1-Dichloroethane 0.8

1,1-Dichloroethene 1.2

cis-1,2-Dichloroethene 26

Dichlorodifluoromethane 0.5

Tetrachloroethene 100

Trichloroethene 12

1/13/92 Chloroethane 0.7

Dichlorodifluoromethane 1.7

Fluorotrichloromethane 0.8

Q2435 21-A Magothy 4/27/92 Tetrachloroethene 0.7

10/28/92 Tetrachloroethene 0.9

Q2442 54 Magothy 9/14/92 1,1,1-Trichloroethane 0.5

Well number

Aquifer

Sampling

NYSDEC JWS date Constituent Concentration

Table 5. Concentrations of selected volatile organic compounds in water from publicsupply wells in Queens County, N.Y.1992--continued
68 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

11/24/92 Bromodichloromethane 6.1

Bromoform 3.4

Chlorodibromomethane 5.1

Chloroform 11

Total trihalomethanes 25.6

Q301 1 Upper glacial 3/9/92 Trichloroethene 0.5

Q3014 58 Magothy 1/13/92 Trichloroethene 0.5

cis-1,2-Dichloroethene 0.5

8/5/92 Dichlorodifluoromethane 0.5

12/10/92 Tetrachloroethene 10

Q303 3 Upper glacial 2/3/92 Chloroform 1.8

Q305 5 Upper glacial 7/27/92 Dichlorodifluoromethane 0.5

12/10/92 Tetrachloroethene 79

Trichloroethene 3.4

Q310 10 Upper glacial 8/17/92 Tetrachloroethene 0.7

11/19/92 Chloroform 0.5

Total trihalomethanes 0.5

Q313 13 Upper glacial 10/28/92 Tetrachloroethene 1.1

Q317 17 Lloyd 9/18/92 Bromodichloromethane 5.1

Bromoform 1

Chlorodibromomethane 1.8

Chloroform 16

Total trihalomethanes 23.9

Q321 21 Upper glacial 8/10/92 Dichlorodifluoromethane 0.6

10/28/92 Tetrachloroethene 2.7

Q322 22 Upper glacial 8/13/92 Tetrachloroethene 2.5

Q323 23 Upper glacial 11/19/92 Chloroform 1.1

Total trihalomethanes 1.1

Q566 17-A Jameco 12/11/92 Chloroform 1.8

Total trihalomethanes 1.8

Well number

Aquifer

Sampling

NYSDEC JWS date Constituent Concentration

Table 5. Concentrations of selected volatile organic compounds in water from publicsupply wells in Queens County, N.Y.1992--continued
 Recent (1992-97) Hydrologic Conditions 69

Table 6. Concentrations of selected volatile organic compounds in water from 

public-supply wells in Nassau County, N.Y., 1992

[Well locations are shown in fig. 13A and 13B. Concentrations are in micrograms per liter (μg/L). 

Detection limit for all compounds is 0.5 μg/L. NYSDEC, New York State Department of Environmental 

Conservation. JWS, Jamaica Water Supply Company]

Well number

Aquifer

Sampling

NYSDEC JWS date Constituent Concentration

N11 15-A Magothy 11/19/92 Chloroform 1.2

Total trihalomethanes 1.2

N11037 15-B Magothy 8/31/92 Tetrachloroethene 0.5

N14 9 Upper glacial 12/11/92 Chloroform 1.6

Tetrachloroethene 1.6

Total trihalomethanes 1.6

N17 20 Magothy 12/8/92 Tetrachloroethene 25

N3720 30 Magothy 10/23/92 Toluene 1.9

N4077 35 Upper glacial 6/5/92 1,1,1-Trichloroethane 2.1

1,1-Dichloroethene 0.7

Tetrachloroethene 1.8

Trichloroethene 14

N4298 35-A Magothy 12/17/92 1,1,1-Trichloroethane 2.3

1,1-Dichloroethene 0.9

Tetrachloroethene 2.1

Trichloroethene 14

2/4/92 Dichlorodifluoromethane 1.5

N4390 40 Magothy 10/22/92 cis-1,2-Dichloroethene 0.6

Tetrachloroethene 1.8

Trichloroethene 0.6

N4512 34 Magothy 8/14/92 Chloroform 0.9

Tetrachloroethene 1.8

Total trihalomethanes 0.9

N5155 44 Upper glacial 4/28/92 Chloroform 1

Total trihalomethanes 1

N5156 44-A Magothy 11/10/92 Tetrachloroethene 0.5

12/17/92 Trichloroethene 22

N6744 44-B Upper glacial 1/2/92 Chloroform 1.4

Total trihalomethanes 1.4

7/16/92 Trichloroethene 0.5

N6745 44-C Magothy 11/18/92 Tetrachloroethene 0.8

Trichloroethene 2.2

N7445 40-A Magothy 7/6/92 Dichlorodifluoromethane 0.5

12/17/92 cis-1,2-Dichloroethene 4.8

Tetrachloroethene 3.7

Trichloroethene 3.8

N7649 57 Magothy 8/3/92 1,2-Dichloropropane 150

11/17/92 1,1,1-Trichloroethane 2.8

12/8/92 1,1-Dichloroethene 1.9

1,1-Dichloropropene 2.7

cis-1,2-Dichloroethene 6.1

Dichlorodifluoromethane 0.5

Fluorotrichloromethane 0.7

Tetrachloroethene 22

Trichloroethene 160

Vinyl chloride 0.8

N7650 57-A Magothy 12/17/92 cis-1,2-Dichloroethene 0.6

Tetrachloroethene 1.3

Trichloroethene 10
70 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Table 7. Concentrations of selected volatile organic compounds in water from 

public-supply wells in Queens County, N.Y., 1996

[Well locations are shown in fig. 14A and 14B. Concentrations are in micrograms per liter (μg/L). 

Detection limit for all compounds is 0.5 μg/L. NYSDEC, New York State Department of Environmental 

Conservation. JWS, Jamaica Water Supply Company]

Well number

Aquifer

Sampling

NYSDEC JWS date Constituent Concentration

Q1747 27 Upper glacial 2/5/96 Tetrachloroethene 0.8

Q1957 5-A Magothy 5/1/96 Dichlorodifluoromethane 3.7

Tetrachloroethene 24

3/5/96 Trichloroethene 0.5

Q1958 10-A Magothy 3/2/-96 Dichlorodifluoromethane 0.8

Q1997 38 Upper glacial 2/8/96 1,1,1-Trichloroethane 1.7

Trichloroethene 0.5

Benzene 0.5

5/3/96 Tetrachloroethene 14

Q2189 45 Upper glacial 4/1/96 Tetrachloroethene 0.6

Q2276 47-A Magothy 4/8/96 Tetrachloroethene 0.6

Q2300 48-A Magothy 4/5/96 cis-1,2-Dichloroethene 1.6

Tetrachloroethene 220

Trichloroethene 34

Q2332 43-A Jameco 5/7/96 Tetrachloroethene 1.4

Trichloroethene 0.9

Q2373 50 Magothy 3/5/96 Trichloroethene 0.5

5/4/96 Tetrachloroethene 11

Q2374 50-A Magothy 5/4/96 Tetrachloroethene 4.2

Q2408 53 Magothy 5/1/96 Tetrachloroethene 10

Q2409 53-A Magothy 5/1/96 Tetrachloroethene 12

Q2432 38-A Magothy 5/3/96 1,1,1-Trichloroethane 5.6

1,1-Dichloroethane 1.1

1,1-Dichloroethene 1.9

cis-1,2-Dichloroethene 6.6

Tetrachloroethene 54

Trichloroethene 7.1

Q2435 21-A Magothy 4/8/96 Tetrachloroethene 1.4

Q3014 58 Magothy 3/5/96 Bromodichloromethane 1

Bromoform 1.5

Chlorodibromomethane 1.2

Chloroform 2.6

5/1/96 Dichlorodifluoromethane 0.9

Tetrachloroethene 11

Q305 5 Upper glacial 5/1/96 cis-1,2-Dichloroethene 0.5

Tetrachloroethene 79

Trichloroethene 5.5

Q310 10 Upper glacial 5/1/96 Chloroform 0.5

Q313 13 Upper glacial 5/1/96 Bromoform 3.8

Chlorodibromomethane 3.4

Dibromomethane 0.5

Tetrachloroethene 0.6

Q321 21 Upper glacial 2/5/96 Dichlorodifluoromethane 0.5

4/8/96 Tetrachloroethene 2.2
 Recent (1992-97) Hydrologic Conditions 71

Table 8. Concentrations of selected volatile organic compounds and one pesticide in water 

from public-supply wells in Nassau County, N.Y., 1996

[Well locations are shown in figs. 14A and 14B. Concentrations are in micrograms per liter (μg/L). Detection 

limit for all compounds is 0.5 μg/L except for dieldrin, which is 0.1 μg/L. NYSDEC, New York State Department

of Environmental Conservation; JWS, Jamaica Water Supply Company]

Well number

Aquifer

Sampling

NYSDEC JWS date Constituent Concentration

N10207 15-E Magothy 4/11/96 Tetrachloroethene 0.5

N17 20 Magothy 5/2/96 Tetrachloroethene 16

N3720 30 Magothy 2/5/96 Tetrachloroethene 1.4

5/7/96 Chloroform 3.5

N4298 35-A Magothy 5/2/96 1,1,1-Trichloroethane 1.4

1,1-Dichloroethene 0.7

Dichlorodifluoromethane 0.7

Tetrachloroethene 1.9

Trichloroethene 10

N4390 40-A Upper glacial 5/8/96 cis-1,2-Dichloroethene 2.6

Dichlorodifluoromethane 0.9

Tetrachloroethene 2.7

Trichloroethene 3.2

N5155 44 Upper glacial 1/3/96 Dieldrin 0.06

N5156 44-A Magothy 5/14/96 Trichloroethene 21

N6745 44-C Magothy 3/5/96 Tetrachloroethene 0.8

Trichloroethene 5.

N7649 57 Magothy 5/2/96 1,1,1-Trichloroethane 3.6

1,1-Dichloroethane 0.7

1,1-Dichloroethene 4.6

cis-1,2-Dichloroethene 6

Dichlorodifluoromethane 0.6

Fluorotrichloromethane 0.6

Tetrachloroethene 22

Trichloroethene 170

Vinyl chloride 1.1

N7650 57-A Magothy 4/18/96 Tetrachloroethene 0.8

5/21/96 Trichloroethene 14
72 History and Hydrologic Effects of Ground-Water Use in Kings, Quens, and Western Nassau Counties, Long Island,

New York, 1800 s-1997

Table 9. Monitoring wells in Kings, Queens, and Nassau Counties, N.Y., at which organic constituents were detected in grou

and 1995

[Well locations are shown in fig. 15. UG, upper glacial aquifer; MAG, Magothy aquifer; --, no detection. Concentrations are in micrograms per liter (μ

Well Aquifer

Constituent and detection limit

PCB

(0.01)

Chlordane

(0.01)

p,p ́-

DDD

(0.01)

p,p ́- 

DDT

(0.01)

2,4-D

(0.01)

Carbon

tetrachloride

(3.0)

Chloroform

(3.0)

cis-1,2-

Dichloroethylene

(3.0)

Dichlorodiflouromethane

(3.0)

1,1

Dichloroethane

(3.0)

1,1-

Dichloroethylene

(3.0)

Freon113

(3.0)

tert-B

meth

ethe

(5.0

K1673 UG -- -- -- -- -- -- 4.8 -- -- -- -- -- 5.K1689 UG -- -- -- -- -- -- 4.8 -- -- -- -- -- -- K2407 UG -- -- -- -- -- -- -- -- -- 4.1 13 -- 1,000 K2482 UG -- -- -- -- -- -- 4.8 -- -- -- -- -- -- 

K2598 UG -- -- -- -- -- -- -- -- -- -- -- -- -- K2610 UG -- -- -- -- -- -- -- 8.4 -- -- 8.7 -- -- 

K2622 UG -- -- -- -- -- -- 15 -- -- -- -- -- -- K3214 UG -- -- -- -- -- -- -- -- 3 -- -- -- -- 

K3216 UG -- -- -- -- -- -- -- -- -- -- -- -- 11 K3218 UG -- -- -- -- -- -- -- -- 14 -- -- -- -- 

K3252 UG 0.9 -- -- -- -- -- -- -- -- -- -- -- -- K3254 UG 0.8 -- -- -- -- -- -- 6.1 -- -- -- -- -- K3255 UG -- -- -- -- -- -- -- -- -- -- -- -- -- K3256 UG 0.1 -- -- -- -- -- -- -- -- -- -- -- -- K3271 UG 0.1 -- -- -- -- -- -- -- -- -- -- -- -- K3425 UG -- -- -- -- -- -- -- 5.5 -- -- -- -- -- 

Q1605 UG -- -- -- -- -- -- 8.9 -- -- -- -- -- -- Q1663 UG -- -- -- -- -- 3.8 -- -- -- -- -- -- -- 

Q1914 UG -- -- -- -- -- -- -- -- -- -- -- -- -- Q2407 UG -- -- -- -- -- -- -- -- -- -- -- -- -- 

Q3003 MAG -- -- -- -- -- -- -- 88 -- -- -- 8.7 -- Q3121 UG -- -- -- 0.02 0.02 -- -- -- -- -- -- -- 7.

Q3644 UG -- -- -- -- -- -- -- -- -- -- -- -- -- Q3659 UG -- -- -- -- -- -- -- -- -- -- -- -- -- 

Q3660 UG -- -- -- -- -- -- -- -- -- -- -- -- -- 

N6703 MAG -- 1.1 0.06 -- 0.07 -- -- -- -- -- -- -- -- 
Recent (1992-97) Hydrologic Conditions 73

Atlantic Ocean

East River

Flushing Bay Flushing

Creek

Little Neck

Bay

QUEENS COUNTY

NASSAU

COUNTY

012345 MILES

0 1 2 3 4 5 KILOMETERS

Jamaica Bay

KINGS COUNTY

40°45'

74°00' 73°45'

EXPLANATION

Base modified from U.S. Geological Survey, 1:100,000;

Long Island West, New York-New Jersey- Connecticut, 1984;

Newark, New Jersey - New York, 1986

Monitoring well with NYSDEC well – identifier .

K1673

K1689

K2407

K2482

K2598

K2610

K2622

K3214

K3216

K3218

K3252

K3254

K3255

K3256

K3271 K3425

Q1605

Q1663

Q1914

Q2407

Q3003

Q3121

Q3644

Q3659

Q3660

N6703

.

.

. .

.

.

.

. .

. .

.

.

. .

. .

.

.

.

.

.

.

.

.

.

K2407

screened in the Jameco-Magothy aquifer). These data 

indicate that the Jameco-Magothy aquifer is more 

widely contaminated in Queens County than in Kings 

County. Surface-derived organic contamination in the 

Jameco-Magothy aquifer in Queens County is 

probably the result of downward flow gradients 

resulting from the large cone of depression generated 

in southeastern Queens County during the earlier 

(mid-1960’s to mid-1970’s) public-supply 

withdrawals. The data in table 9 indicate more 

widespread organic contamination of the upper glacial 

aquifer in Kings County than in Queens County 

(tables 5 and 7), which, in turn, suggests a greater 

number of point sources of contamination in Kings 

County. The lack of organic contamination in the 

Jameco-Magothy aquifer in Kings County may 

indicate the limited use of synthetic organic 

compounds prior to 1947, when these compounds 

could have been drawn into deeper aquifers by 

extensive public-supply withdrawals.

Figure 15. Locations of monitoring wells in Kings, Queens, and western Nassau Counties, 

N.Y., at which organic compounds were detected in 1992-93 and 1995.
74 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

Table 10. Revised hydrogeologic framework at selected new wells in Kings and Queens Counties, N.Y.[Well locations are shown in figures 6G, 6H, and 6I. All elevations are in feet above or below (-) sea level; all thicknesses are in feet. ABS, unit is absegreater than; < less than. Numbers in parentheses are from Buxton and Shernoff (1995) in the absence of new values]

Well

number

Land

surface

elevation Well depth

Well

data

and

information

source*

Upper

glacial

aquifer

Gardiners 

Clay

Jameco 

aquifer

Magothy 

aquifer Raritan clay

Lloyd 

aquifer

Bedrock

Remar

Thickness

Top

of

unit

Thickness

Top

of

unit

Thickness

Top

of

unit

Thickness

Top

of

unit

Thickness

Top

of

unit

Thickness

Top

of

unit

K3405 33 220 PUB

LOG

160210

-127ABS

20

ABS

-147-147

50

>10

200ND

30

ND

-235ND

100

ND

-330ND

180

ND

-510

ND

Framework consistent with that in Bexcept Gardiners Clay is absent.

K34061 14 175 PUB

LOG

~50

105

 -64ABS

~100

ABS

-164-119

5055

ABSND

ABS

ND

ABSND

ABS

ND

ABSND

ABS

ND

-214-174

Well is near northwest extent of Gardpresence of these is uncertain. Gardiaquifer is present. Bedrock is about 4estimates.

K3407 8 405 PUB

LOG

158180

-150ABS

40

ABS

-190-172

3040

-220-212

110

75

-330-287

120

<110

-450ND

200

ND

-650

ND

Framework consistent with that in Bexcept Gardiners Clay is absent.

K34102 62 395 PUB

LOG

162185

-100-123

50

110

-150

ABS

130

ABS

ABS-233

ABS

63

-280-296

4037

ABSABS

ABSABS

-320-333

Framework consistent with that in BGardiners Clay is absent; Magothy a

K3414 7 440 PUB

LOG

170

(-170)

-163ABS

30

ABS

-193

(-168)

2534

-218-202

155235

-373-437

140

ND

-513ND

205

ND

-718

ND

Jameco aquifer is absent; Magothy aclay is deeper than that in Buxton an

K3424 75 75 PUB

LOG

195

>75

-120ND

20

ND

-140

ND

70

ND

ABSND

ABS

ND

-210ND

40

ND

250ND

130

ND

-380

ND

Boulders caused difficult drilling.

K34313 81 390 PUB

LOG

206250

-125-169

2595

-150

ABS

50

ABS

ABS-264

ABS

<45

-200ND

100

ND

ABSND

ABS

ND

-300

ND

Magothy aquifer is not this far north aquifer is at least 45 feet thick. Jame

Q35874 83 475 PUB

LOG

213195

-130-112

100125

ABSABS

ABSABS

ABSABS

ABSABS

-230-237

70

>155

ABSABS

ABSABS

-300

>-392

Raritan clay is thicker and bedrock ithan in Buxton and Shernoff (1995) bedrock).

Q3589 22 325 PUB

LOG

9798

 -75 -76

7565

-150-141

200136

ABSABS

ABSABS

-350-277

175

>26

-525ND

225

ND

-750

ND

Framework consistent with that in BJameco aquifer is thinner.

Q35935 15 225 PUB

LOG

1060

ABSABS

ABSABS

ABSABS

ABSABS

ABSABS

ABSABS

-5-45

9594

-100-139

7071

-170-210

Framework consistent with that in Bupper glacial aquifer is thicker; 40 fe

Q36276 77 540 PUB

LOG

297150

ABS -73

ABS

162

ABSABS

ABSABS

ABS-235

ABS

218

-220-453

140

ND

-360ND

140

ND

-500

ND

East-west extent of erosional channeClay and Magothy aquifer encounter

1 Deep well of doublet with K3423.2.Deep well of doublet with K3425.3.Deep well of doublet with K3430.4.Deep well of doublet with K3649.5.Deep well of doublet with K3604.6.Deep well of three-cluster with Q3628 and Q3629.*PUB, published value (Buxton and Shernoff, 1995); LOG, Interpreted from lithologic and geophysical logs.
Summary and Conclusions 75

Revised Hydrogeologic Framework

Data from the 29 new wells enabled a refinement 

of the previously described hydrogeologic framework 

in Kings and Queens Counties. This updated 

information is outlined in table 10.

The hydrogeologic information given in table 10 

represents only 11 of the 29 new monitoring wells 

described earlier; the remaining 18 new wells are 

omitted because they are shallow (upper glacial 

aquifer) wells that provide no new hydrogeologic 

information, or are the shallow wells of a well doublet 

or triplet. Each well in table 10 has two rows of data—

the upper row presents data interpreted from plates 2 

and 3 of Buxton and Shernoff (1995), and the lower 

row presents information derived from drillers’ logs 

and geophysical logs of the new wells. (Only a few 

cores were obtained during drilling.)

The new hydrogeologic information obtained in 

this study generally is consistent with that presented in 

Buxton and Shernoff (1995), but because new wells 

were installed in areas where information was lacking, 

each provided a refinement of the hydrostratigraphy in 

its respective area. In addition to differences in 

thickness of the various units, a few changes in the 

updip extent of some units were defined. The revised 

hydrogeologic framework is summarized in table 10; 

other information provided by the new wells is 

summarized below. 

Upper Glacial Aquifer

The only new data on the upper glacial aquifer 

pertain to its thickness (table 10). No new information 

regarding its areal extent is available, however, 

because this unit is present at land surface in nearly all 

of Kings and Queens Counties.

Gardiners Clay

No evidence of the Gardiners Clay was found in 

wells K3405, K3407, or K3414 in south-central and 

southern Kings County; this result suggests an 

elongated hole in the Gardiners Clay in that area, 

similar in size to two other holes in the Gardiners Clay 

to the east in Kings and Queens Counties. The 

presence of Gardiners Clay in well Q3627 extends the 

previously defined northern limit about 0.5 mi 

northward.

Jameco Aquifer

The absence of the Jameco aquifer in well K3410 

indicates that the northern limit of these deposits is 

more than 1 mi south of its previously estimated 

position. New data indicate no other revisions to the 

extent of the Jameco aquifer.

Magothy Aquifer

New data for the Magothy aquifer are in fairly 

close agreement with data of Buxton and Shernoff 

(1995), except those data from wells K3410 and 

K3431. These wells are northwest of the Magothy 

aquifer’s northern extent as defined by Buxton and 

Shernoff (1995) and contain about 50 ft of gray sand 

and clay similar to that found in the Magothy aquifer. 

These wells are surrounded by wells that do not 

penetrate the Magothy aquifer; thus, the question 

remains as to whether wells K3410 and K3431 

penetrate an isolated stringer of the Magothy aquifer. 

A second refinement to the northern extent of the 

Magothy aquifer is in Queens County, near the buried 

channel. Wells Q3627 and Q3589, along the eastern 

and southeastern extent of the channel, provide new 

data on channel boundaries.

Raritan Clay and Lloyd Aquifer

Four of the new wells were drilled deep enough 

to penetrate the Raritan clay, but only one provided 

new data. Well K3410, in central Kings County, 

penetrated the Raritan clay about 1 mi east-southeast 

of the previously defined northern limit of this unit. 

Only three of the new wells were drilled deep enough 

to penetrate the Lloyd aquifer. The differences in unit 

thickness are presented in table 10; no changes in the 

extent of the Lloyd aquifer as defined by Buxton and 

Shernoff (1995) were found.

SUMMARY AND CONCLUSIONS

Pumpage from the aquifers underlying Kings and 

Queens Counties during 1904-47 averaged 

120 Mgal/d. This resulted in extremely large 

drawdowns and saltwater encroachment, and 

necessitated the cessation of all public-supply 

withdrawals in Kings County in 1947. Withdrawals in 

Queens County were increased to compensate for the 

shutdown in Kings County, and pumping shifted from 

the upper glacial aquifer to the Magothy aquifer to 
76 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

avoid contamination. By 1974, all remaining publicsupply wells in Queens County were shut down except 

for JWS wellfields in eastern Queens County, which 

continued to pump at an average rate of about 

57 Mgal/d. The elimination of public-supply 

withdrawals in Kings and western Queens Counties 

resulted in a steady recovery of ground-water levels in 

these areas. By 1983, ground-water levels in Kings 

County were close to predevelopment levels (1903), 

and contamination by saltwater had partly dispersed 

and become diluted. In contrast, all three aquifers 

(upper glacial, Jameco-Magothy, and Lloyd) in eastern 

Queens County showed a large cone of depression 

toward which the freshwater-saltwater interface in the 

Jameco-Magothy aquifer was moving. Similar 

landward movement of the interface had been detected 

in the Lloyd aquifer, although the location was 

estimated to be offshore.

Elevated nitrate and chloride concentrations 

(above background levels) in the upper glacial aquifer 

in 1983 indicated widespread contamination from land 

surface. Some effects of surface contamination also 

were present in the Jameco-Magothy aquifer in areas 

of good hydraulic connection with the upper glacial 

aquifer. Ground water in the Lloyd aquifer in 1983 still 

was largely uncontaminated, although the observed 

cone of depression and the hydraulic connection 

provided by the buried channel have been a cause for 

concern over the potential for the migration of 

contaminants into the Lloyd aquifer.

Recent reductions in public-supply withdrawals 

in Queens County from 57 Mgal/d in 1983 to 

24 Mgal/d in 1991 and to 14 Mgal/d in 1996 have 

resulted in the recovery of ground-water levels in the 

eastern part of Queens County. Concurrently, 

increased withdrawals for industrial supply and 

dewatering in Kings County have resulted in local 

drawdowns in some areas, although water levels 

throughout Kings County are still above sea level. 

By 1997, the upper glacial aquifer in Kings 

County generally was stable, and water levels at most 

wells were between 0 and 10 ft above sea level. The 

two large depressions in the 1983 Queens County 

water table had recovered, and water levels had risen 

as much as 30 ft at certain wells. Similarly, the water 

table in western Nassau County, adjacent to past cones 

of depression in Queens County, showed some 

recovery. The result has been a shift in the general 

direction of ground-water flow from southwestward in 

1983 to south-southwestward in 1997.

The 1996 potentiometric surface of the JamecoMagothy aquifer in Kings County was delineated from 

data from six wells, as compared with two wells used 

in 1983. Water levels in these wells in 1996 were 

similar to those measured in 1983 and indicated nearequilibrium conditions. In contrast, water levels in all 

15 Jameco-Magothy aquifer wells in Queens County 

had risen sharply—by as much as 27 ft. Available data 

indicate that the potentiometric surface in 1996 was 

above sea level throughout Queens County. Water 

levels in the Jameco-Magothy aquifer in western 

Nassau County also have been recovering since 1983. 

Water levels at wells closest to the coast showed little, 

if any, change since 1983, whereas wells in westcentral Nassau County, adjacent to the 1983 cone of 

depression in eastern Queens County, had recovered 

by as much as 18.6 ft by 1996. 

The recent potentiometric surface of the Lloyd 

aquifer in Kings County is defined by only two wells; 

one was measured in 1983 and 1996, and the other 

only in 1996. The former measurements indicate a 

water-level recovery of 4.5 ft in southern Kings 

County since 1983, and the latter measurement 

indicates a water level of 8 ft above sea level. More 

data are available on the Lloyd aquifer in Queens 

County than in Kings County; all wells in Queens 

County showed increases in water levels from 1983 to 

the present. The largest recoveries were at publicsupply wells in central Queens County, where water 

levels increased as much as 35 ft. 

Recent water-level recoveries generally have 

resulted in the dilution and dispersion of residual 

saline and nitrate-contaminated ground water. Dilution 

and dispersion probably have been occurring since 

public-supply withdrawals were halted in Kings 

County in 1947, and in Queens County in 1974. 

Chloride concentrations at 75 percent of wells 

screened in the upper glacial aquifer in Kings and 

Queens Counties have decreased or remained the same 

since 1983. Similar trends in chloride concentrations 

are evident in the Jameco-Magothy aquifer in Kings 

and Queens Counties, although data from Kings 

County are limited. Geophysical logs, together with 

chloride data, indicate that the freshwater-saltwater 

interface in southern Kings County may be 1.5 mi 

farther inland than estimated in 1983. This result does 

not suggest that the interface has moved farther inland 

since 1983, but that its inland extent may have been 

underestimated in 1983. Recent chlorideconcentration data from the Lloyd aquifer, although 

limited, indicate that concentrations are similar to 
Summary and Conclusions 77

those of 1983. Data from new wells indicate that saline 

ground water in the Lloyd aquifer is about 7 mi farther 

inland than estimated in 1983. These data are in 

question, however, and additional information would 

be necessary to evaluate the position of the interface.

Nitrate concentrations at the majority of wells 

screened in all three aquifers in Kings, Queens, and 

western Nassau Counties have declined since 1983, 

probably in response to the dilution, degradation, and 

dispersion that have resulted from the long-term 

water-level recovery.

Data on organic-compound concentrations at 

public-supply wells in Queens and western Nassau 

Counties, and for monitoring wells in Kings, Queens, 

and western Nassau Counties, are available. The 

organic-compound data set for the monitoring wells is 

the first of this type of data collected in the study area.

Queens County had 39 public-supply wells with 

detectable concentrations of organic compounds in 

1992; half of these were screened in the upper glacial 

aquifer, and half in the Jameco-Magothy aquifer. The 

most frequently detected compounds were 

tetrachloroethene, chloroform, total trihalomethanes, 

and trichloroethene; concentrations of all compounds 

ranged from 0.5 μg/L to 150 μg/L. These compounds 

were detected in a higher percentage of upper glacial 

aquifer wells than in Jameco-Magothy aquifer wells.

Nassau County had 16 public-supply wells with 

detectable concentrations of organic compounds in 

1992, 25 percent (4) of which were upper glacial 

aquifer wells, and 75 percent (12) Jameco-Magothy 

aquifer wells. The most frequently detected 

compounds were the same as in Queens County, and 

concentrations ranged from 0.5 μg/L to 160 μg/L. 

Tetrachloroethene and trichloroethene were detected 

most frequently in the Jameco-Magothy aquifer wells, 

whereas chloroform and total trihalomethanes were 

detected mostly in upper glacial aquifer wells.

Queens County had 19 public-supply wells with 

detectable concentrations of organic compounds in 

1996. Seven of these were upper glacial wells, and 

about 12 were Jameco-Magothy aquifer wells. The 

most frequently detected compounds were 

tetrachloroethene and trichloroethene; the 

concentrations of all compounds ranged from 0.5 μg/L 

to 220 μg/L. Tetrachloroethene was detected in the 

same percentage of upper glacial aquifer wells as 

Jameco-Magothy aquifer wells, whereas 

trichloroethene was detected more frequently in 

Jameco-Magothy aquifer wells.

Nassau County had 10 public-supply wells with 

detectable concentrations of organic compounds in 

1996; two of these were upper glacial aquifer wells, 

and eight were Jameco-Magothy aquifer wells. The 

most frequently detected compounds were 

tetrachloroethene and trichloroethene; the 

concentrations of all compounds ranged from 

0.06 μg/L (dieldrin) to 170 μg/L (trichloroethene). 

These compounds were detected most frequently in 

the Jameco-Magothy aquifer wells.

Detectable concentrations of at least one organic 

compound were found in 26 of the 108 monitoring 

wells in Kings, Queens, and Nassau Counties in 1992-

93 and 1995. Organic compounds were detected in 

twice as many wells in Kings County as in Queens 

County, and in only one well in Nassau County. The 

most commonly detected organic compounds were 

tetrachloroethene and trichloroethene, followed by 

chloroform. Maximum concentrations of all organic 

compounds measured ranged from 0.02 μg/L 

(pesticides) to 150 μg/L for tetrachloroethene. Of the 

25 monitoring wells in Kings and Queens Counties 

with detectable concentrations of organic compounds, 

24 were upper glacial aquifer wells, whereas most of 

the public-supply wells in Queens County with 

detectable concentrations were Jameco-Magothy 

aquifer wells (1992 and 1996 data). This result 

suggests that the public-supply wells screened in the 

Jameco-Magothy aquifer in Queens County drew 

organic contaminants downward from a surface source 

during the 1960’s and 1970’s, when a large cone of 

depression was present. In contrast, limited use of 

synthetic organic compounds prior to 1947 would 

minimize the possibility of these contaminants 

presence in the deeper aquifers. In addition, any 

organic contaminants that were drawn down into 

deeper aquifers in Kings County before 1947, when 

pumping was extensive, probably have had time to 

become degraded, diluted, and dispersed. 

The installation of new monitoring wells in the 

study area from September 1992 through October 

1995 has resulted in a refinement of hydrogeologic 

boundaries, both laterally and with depth. Although 

most of the refinements are relatively minor, they 

could prove valuable for localized studies in the future.
78 History and Hydrologic Effects of Ground-Water Use in Kings, Queens, and Western Nassau Counties, Long Island,

New York, 1800s-1997

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