Groundwater quantity and quality in the New Jersey coastal zone a staff working paper

[From the U.S. Government Printing Office, www.gpo.gov]

COASTAL MHz
INFORMATION CENTER

t it

Groundwater Quantity and Quality in the New Jersey Coastal Zone:
A Staff Working Paper

Michael Hochman

New jersey Department of Environmental Protection
Division of Marine Services
Of f ice of Coastal Zone Management
P. 0. Box 1889
GB Trenton, New Jersey 08625
1205
N4
H63 Novemb '1976
1976

I
FO
N E t
1"04 CENTER
Note: This staff working paper is one of a series of issue

and Policy Alternative Papers presenting facts, analyses,

and conceptual policy alternatives on coastal resources and

coastal land and water resource@s. The purpose of this draft

document is to stimulate discussion and comments that will

assist preparation of the management program for the New

Jersey coastal zone. This report was prepared in part with

financial assistance under the Coastal Zone Management Act,

P.L. 92-583.
------------

Comments, criticisms, additions, and suggestions are welcome
,and should be addressed to the Office of Coastal Zone Manage-

ment.

DEPARTMENT OF COMMERCE NOAA
COASTAL SERVICES CENTER
2234 SOUTH HOBSON AVENUE
CHARLESTON 29405-24 13

ProPeXtY Of CSC Library

Ac-i

CONTENTS

PAGE

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

@I. Issues:

A.. Groundwater Quantity .................. ........ 2

B. Groundwater Quality ............................ 2
II. Policy Alternatives .................................. 4
-III. Physical Characteristics and Natural Functions ...... 8

IV. Analysis
A.- Groundwater Quantity ............................. 15
B. Groundwater Quality ............................. 17

Appendices

A.. Regional Reports

1. Hudson River .............................. 24

2.- North Shore ............... * ................ 29

3. Central Shore ............................. 36

4. South Shore ................................ 42

5. Delaware Bay .............................. 45

6. Delaware River Water Front ................ 52

B. Sources ......................................... 57

INTRODUCTION

The loss or severe reduction of our groundwater resources

and the danger of local groundwater contamination is a real

and potential problem in areas in and adjacent to the coast.

The depletion of this valuable, readily available, natural

resource and salt water intrusion and local pollution may

severely disrupt the coastal population and its economy by

limiting potable water supplies.

This'-paper is intended to further debate on important

groundwater issues. The first section briefly defines these

issues in the coastal area and then presents alternative

policies which could be part of the coastal zone management

program in New Jersey.

Section III provides characteristics of groundwater in

New Jersey's coastal area in terms of existing and potential

quantity and quality.

Section IV analyzes natural processes and man-made

activities that affect groundwater quantity and quality.

Two appendices conclude the paper. First, coastal zone

regions are examined individually and problems specific to

the region are highlighted.

Finally, the sources used to support and reference the;`_

text. are presented..

I. ISSUE

A. Groundwater Quantity

In. some areas of the coa-stal zone localized scarcity of

groundwater is becoming an increasing problem. This applies

expecially to the intensely developed areas primarily the

Hudson River Waterfront and Newark Bay areas, Monmouth,

Salem,.and-Cape May.counties.

Pumping of groundwater-,,-and the reduction of aquifer

recharge by the construction of storm water drainage systems

that discharges into surface wat er, has led to a scarcity of

groundwater in localized parts of-the coastal zone. If the

trend of groundwater deplet*:'L@o'n'continues it will lead to a

loss of economic benefits resulting from the loss of a cheap

high quality water supply. There is also a side effect of

overpumping and consequently lowering of the water table

that could change the base flow conditions of streams altering

the ecological conditions of an aquatic environment.

B. Groundwater Quality

The quality of groundwater supplies in the Coastal Zone

has been locally threatened in re cent years by contamination,

from man-made pollutants to the water table aquifer. This

has resulted in the abandonment of many wells.

Secondly, salt water intrusion threatens groundwater

existing along the immediate Atlantic Coas.t over most of the

-2-

Coastal Plain.

Saltwater has already contaminated some water supplies

along the coast and some wells have had to be abandoned.

Increasing population and concentrated development will

.eventually worsen the situation. This will result in the

loss of economic benefits because ofthe forfeiture of a

cheap water supply.

-3-

II. POLICY ALTERNATIVES

Planning and regulations, are needed to maintain an ample

supply of grou ndwater.

1. The safe sustained yield of local aquifers should

be established. This is the amount of water that

can be constantly withdrawn without unacceptable

change to water table elevation and salt water
intrusion. This data ca@n- be partially obtained

from the digital ccrtiputer simulation model that

USGS,has bpen undertaking. Aquifer models have

been completed and calibrated for the following

aquifers within the coastal zone: Raritan-

Mogothy, Englishto-@-a' and Wenonah-Mt. Laurel. This

model will show the best location of wells and4-

quantity of withdrawal.

In order to assure the safe sustained yield the

following should be included:

.(a) protection of prime recharge areas

Prime recharge areas could be delineated. Criteria

..for zuch tdam d-F-, @--*@@* on would include: permeability

of soils, land cover, depth to seasonal water

table,elevation of the area and geology.

Development over these areas could be required to-,_

respect the recharge conditions of the soils and

geologic formations. Standards would include

-4-

limitations to the amount of impermeable surfaces

that water retention basins and/or constrction of

wells to artificially recharge endangered ground-

water aquifers. This is being.done in Long Island,

New York.

(b) Proper placement'of new wells on the areas

not covered by aquifer models

Placement of new wells could be based on ground-

water availability,-..-,z,,nd quality. Criteria would be

,specific to different areas and include: the

number of wells to be drilled and the amount of

water allowed to be pumped from each well-

theoretically derived safe sustained yield, and

placement of wells inxelation to each other-.

Spacing requirement should, whenever possible, be

based on local factors because no one set of

distances will be adequate and reasonable for all

conditions. In areas where "undesirable" conditions

exist safe distances should be extensive. In

areas possessing especially "favorable" conditions

lesser dis-tai=.e_-_ might be acceptable if approved

by the enforcing agency.

In the determination of the factors which will

govern the selection of a safe distance the follow-

ing mimimun factors should be evaluated: the type.t;

and location of the sources of potential and

-5-

existing contamination; geologic and hydraulic.

characteristics of the material between the land

surface and water table, the water table and

bedrock, seasonal depth to water, its direction

and rate of'movement, and the mathematically

derived effect of well pumping on the direction of

groundwater movement between the source of contami-

nation and the well

2. Preventive and revi'4A`ial measures could be taken to

control saltwater intrusion. Some of the threatened

areas are identified by USGS and delineated,

thereby action could be-taken in these areas to

combat salt intru@Aon. Measures taken could

include wells drilled to artificially recharge

endangered aquifers to maintain a pressure head so

as to control saltwater intrusion, and stringent

regulations concerning the utilization of-ground-

water overpumpage of aquifers threatened by

intrusion. Also, construction of tidal dams to

maintain freshwater storage in the reaches of

-streams that are subject to saltwater flooding

during high severe storms.

3. More stringent regulations should be developed

concerning point and non-point pollution sources
and @_heir relationship with recharge of aquifers._:@-
Minimum distances should be set between sanitary
landfills and wells. Certain types of materials

-6-

such as industrial wastes, dredge spoils etc. to

be dumped should be regulated in prime recharge

areas.

The inventory of non-point pollution sources

affecting groundwater in the coastal zone would

lead to measures resulting*in the amelioration of

specific non-point pollution impacts. For example,

soil and conservation practices are one of the

most effective pri)-
,,.,@S@ipal controls for reducing
potential pollution from agricultural watersheds

(see Water Quality Issue Paper).

-7-

III. PHYSICAL CHARACTERISTICS AND NATURAL FUNCTIONS

Portions- of two geolo gic provinces of greatly differing

water-bearing capacities are located within the.New Jersey

Coastal Zone, Figure 1. Differences exist because the geo-

logic formations enclosing each province contrast greatly in

their ab ility to receive and to store water.

The northern province, the Piedmont Plateau, which

includes the Hudson River Waterfront and Newark Bay, is

composed of consolidated material where the majority of its

groundwater is retained in.the hard, extensively fractured,

sedimentary_;@pcks. The thinner and less pervious soils and

steeper slopes, permit less infiltration, perhaps one-fourth

to one-third as much as in South Jersey, and the average

time bofore the shallow groundwate.r'appears in the'streams

is much less. Local anomalies provide no water., such as the

basalts of theWaychung Mountains. Large amounts of ground-

water also exist in the uncosolidated glacial drift occupying

ancient river valleys. Glacial deposits of unsorted material,

ranging from clay particles to large boulders, from sheets

of unconsolidated drift that cover much of the Piedmont with

a depth of 15-20 feet. However, the drift-filled valleys

may be hundreds of feet deep andthe aquifers within them

can, if impermeable layers of clay and marl overlie them,

become artesian'.

The New Jersey po rtion of the Atlantic Coastal Plain is

composed of unconsolidated silts, clays, sands, and gravels..
It is-bou'nded on the north by a line stretching from Trenton

to Raritan Bay and includes three-fifths of the State. it

stretches 100 miles outward into the Atlantic Ocean.

Perhaps 40 percent of out-45 inches of precipitation

falling each.year on the sandy.Coastal Plain would infiltrate

into the ground and most of that would reappear days, weeks,

or months later in the springs or seeps that feed the streams.

There is recharge to two physiographic provinces of the

Coastal Plain, Figure 1;

1. In the area of the Inner Coastal Plain there is.

recharge to the large capacity sand formations,

true aquifers. These aquifers outcrop along the

Atlantic Coast northoof about Neptune City up:to

Sandy Hook and around the Raritan Bay and also the

area of the coastal zone up-river from Lower

Alloways Creek.

The aquifers dip gently to the southeast from the

outcrop area and underneath the Outer Coastal
Plain.'s impermeable layers of clay and marl that

prohibit the flow of water through them. The

water exists under pressure. Wells are drilled

through the Outer Coastal Plain to great depth to

tap these formations, see Figure'2.

The Outer Coastal Plain, larger in the area than

the Inner Coastal Plain, has at the surface Pleis-

-9-

NEW JERSEY
SCALE 141.000.000
5 0 0 10 If mlles

Figure 1. Physiographic prov*incbs,in the coastal area of N.J.

zoo'

7
Tkw
-7
-7

Kmr
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EXPLANATION
AOUIFERS
-2000- AQLII'rAkOS

Tmq mooosquan F
table aqv4e'
T@. X"Xwood pdrn`@s;oft Tht Horve,sfon o&d
fee Xrb Red Oonx son4
03
TO Vinceetown Formaikon N-esing Famv?@P,
Kmt Morsnolitow, frMa,iQh
-@fo' X-O woodbuey
Lourtf
K" Sand and
QQ. to, Xrn@ MetchOhNWe Formaj,on
Oh FQ'mai,an

wn
An'- Formation
oqu. fer
Kfhr Ro,@jor` a
Fp, m "@ ul%' 9
Pro-cretaceous "Ysto)lme
btd(.Ck

Wet
vort'401 scale O'eoj("
.ale,

Figure 2. Geohydrologic 8ection, Coastal Plain".

tocene sand and gravels, the Cohansey Formation,

and the underlying Kirkwood Formation all of.which

are essentially acting as one hydrologic unit..

While there are areas underlain by clay or with

appreciable silt or clay in the sands, which

therefore are not as good for percolation of

rainfall, most of the area is a sand which will

absorb about 1/2 inch per hour of rainfall.

Therefore, unless the ground is frozen there is

-practically no surface runoff because rain storms

seldom exceed this hourly rate.

This unconfined or semi -confined unit, receives

almost all initial recharge from precipitation and

streams. It'then may 'recharge underlying aquifers

through direct contact or breaks in overlying

layers of impermeable clay and marl.

The sandy Coastal Plain is@-water-bearing to thicknesses

of 6,000 feet above bedrock near Cape May but thinning down

from 30 to 50 feet.above bedrock along the Delaware River

and along the fall line from Trenton to Perth Amboy. In the

Coastal Plain some of the large,wells are screened at depths

of 600 to 800 feet, but most are less than 300 feet deep.

In total, some 22 to 25 inches of out 45 inches of

rainfall is lost each year to evapotranspiration of deep
percolat ion to the oceans. The remainder, which may vary

from 8 inches in a drought year to 35 inches in the wettest

years, runs off thro ugh the groundwater-.surface.stream,

system to the ocean. is worthy of note, however, that

evapotransp iration takes first claim on precipitation and

does not vary greatl y from a dry year to a wet year in New

Jersey.. The residual 8 to 35 inches, averaging about 21
I
inches, is available for immediate use by 'Man or for storage

above,.ox-.below,,gtound,,. We_are .,only withdrawing about one-

,fourth of the 21 inches of annual precipitation not claimed

@by evapotranspiration. A much-larger proportion could be

withdrawn with.additional surface storage and greater use of

groundwater in areas of surplus. If groundwater is not

used, its potential is not realized and storage space under-

.gr ound is not created into wT@ich_precipitation can infiltrate

to replenish the supply. If pumping exceeds the natural

recharge rate for long periods, then groundwater levels

drop, but this is only happening in a few centers of heavy

pumping.

New Jersey Coastal Zone groundwater quality at a given

place is very constant from day to day and year to year.

However, over the State there are areas of salty water-

(perhaps 10-percent--af--t-ot,,al,---volume), pockets of high iron

content, very hard water, or high in content of other

dissolved minerals, see Table 1. All except the salty
water is potable after conventional treatment and perhaps

one-third is potable without treatment. Chlorination and

softening, if needed, are the only treatment given to most

.groundwaters used for public supply, though some is also

-13-

treated for iron removal.

Table 1.

Range of Impurities in the Following Coastal Zone

Aquifers:

Raritan and Magothy Formations,,Englishtown Formations,.

Wenoah Formation and Mount Laurel Sand, Kirkwood

Formation, and water ta]@@-o aquifers.

-U.S. Public Range of Impurities

Health S-r-lp-ndards Maximum minimum

.Iron 0.3 114 0

Bicarbonate - 382 0

Sulfate 250 465 0

Chloride 250 6800 1.8

Nitrate 20 82 0

Dis. Solids 500 3440 14.0

@PH 9.1 3.8

Hardness 345 2.0

Temperature 86,F 41 F

units in parts per million (ppm)

Source: USGS Special Reports

-14-

Groundwater is ecologically vital to the Coastal Zone.

It is the source of most stream flow within the zone. Al 1

freshwater ecosystems'are dependent on groundwater to provide

a unique aquatic environment associated with lakes, rivers,

and streams. Groundwater is also the primary water source

for most terrestrial vegetation and human consumption.

IV. 'ANALYSIS

A. Groundwater Quantity

The artificial removal of large quantities of water

(over-pumping) from the aquifers has no doubt altered con-

.siderably the pattern of mov%@ment in them. Increased water

development may be expected to cause additional changes.;--

The removal of water from an aquifer by a well, or well

field, lowers the head around the well enough to induce

the flow of an equivalent quantity of water toward the well.

The depression of head around the well is called the cone

Umping*...-.,.we...::..

b''
[email protected]:pvmping
well
Co

A'.
'-Aqtji.

. .. ......

b
Impermea le rock

Figure 3 Cones of depression.

Therefore, the cone of depression of each new well must

expand until it has induced additional recharge to the

aquifer or intercepted discharge equal to the quantity of

water removed by the.well. The process may take. a considerable

period of time because of large quantities of water may be

removed from 6torage in the aquifer and in the adjacent

4quic.ludes. When the process has been completed,however,

new flow lines have been diverted.from their original courses

as water moves toward the well.

Impervious surfaces and construction of storm water

drainage systems reduce the amount of.rainwater infiltrating

into the ground, Table 2. The water flows overland to near-

by streams instead, consequently-1 heavy pumpage creates,

permanent cones of depression.

TAble 2: Impervious Surface and Storm Sewer of Residential

Development.

Development Amount of Impermeable Storm

Type Surfaces Sewered

1 DU/2 Acres 5%

1 DU/Acre 10%

2 DU/Acre 20% 20%

4 DU/Acre 33% 33%

8 DU/Acre 50% 50%

-16-

8 DU/Acre 75-100% 50-100%

Clustered

Urban _10%

Source: Caputo, Hochman, and Hougen, 1974

The present state of groundwater resources show in

localIzed ar-.,eas ..a _-reduced -Level -o,f .,water due to pumping. -and.

to a much lesser degree development of our recharge areas.

Based on available data, grouxi' ater levels will continue to

decline at the present rate of usage. The possibility

exists that water supplies in some areas could fall short of

demand and this is more likely in-the event of a prolonged
drought. Planning is needea'@L ,-,ensure an ample supply of

groundwater from the coastal zone-_ in the future.

B. Groundwater Quality

Man's activities constitute the prime source of the

contamination of groundwater aquifers. There exist two

major categories of pollutants, man-made pollutants and man-

induced pollutants. Contamination of aquifers with man-made'

@h
point pollutants. exist on the

surface which are capable of seeping into the ground with

recharge from precepitation. Permeable soils are more

susceptible to seepage than soils containing a significant

proportion of silt and clay. Potential pollutants may be
found in sanitary land fills',sewage waste disposal sites
(seethe Solid Waste Issue Paper for specifics), septic

-17-

tanks. Figure 4 shows the introduction of contaminants into

an aquifer from a septic tank.

Drain field

71
j Septic
4-
7-' Zone of aeration Z@_@
Unsaturated zDne
RechaRe
percolation t:t_@
tank

atertable --7-=
mound

Aqu

Figure 4. Percolation through zone of aeration. Most

of the natural removal or degradation processes

function under these conditions.

a Common biological wastes are naturally removed by those

processes that operate under condition of aeration.-

Almost all of the suspended solid material is filtered out

by the upper few inches of soil. However, stable contaminants

in solution such as phenolic compounds or synthetic detergents

may,still percolate through the aquifer to a well.

Contamination of aquifers from man-made non point

source of pollution comes from polluted streams that recharge

groundwater aquifers, agriculture roads, air borne wastes.

Figure 5 represents a major problem facing those water
users with heavy pumpage near polluted streams. If a stream

that is the source of water for a well field is contaminated

_18-

by materials that are not naturally degraded under saturated

..underground flow conditions, groundwater in the vicinity of,
the well will in turn be poiluted.

Pumping

River water tab e
Contaminated
alluvium
surface water
Pumping water level

Induced recharge

Figure 5. Induced infiltration from stream. Stream

pollution can result in "groundwater" pollution.

Natural purification is limited to those

processes requiring no oxygen.

There are two classes of potential pollutants from

agricultural cropland. These include sediment, and agricul-

tural chemicals. Sediment may be one of the most costly and

serious of all pollutants from agricultural cropland, although

it is often overlooked. The importance of sediment as a

pollutant comes from the high costs resulting from sedi-

mentation and filling of,strTe-ams, causing reduction in

car rying capacity, and increased possibility of flooding.

Agricultural chemicals, including modern pesticides and

chemical fertilizers can be carried off of crop land in two

forms:'. (a) soluble forms in@runoff or in percolate water,

(b) insoluble forms or attache d to colloidal sediments.

-19-

Roads and highways, collect oil and gasoline spills,

tire tread dust etc. Precipitation will wash off the pol-

lutants and runs off as overland flow. A part of water

entering the roads percolates downward to the soil zone and

eventual ly to the water table.

The airborne substances such as chromium can be introduced

to the aquifer in several ways. For instance, chrome-laden

dust from an electroplating company is discharged through

ventilators on the roof. Some of the dust settled to the

ground, where it accumulated until rainfall washes it down

to the water table, as dipicted in Figure 6. A general

relationship is shown between precipitation and chromium

contamination in the township wells.
Airborne chrome-ladan dust /Z
J

Ploting company
PreCipi'lotion

0 To municipal
supply

71
S'!
0

a.,. W rto 0, 0
0 0

'o.
0 7
Sand and gravel aquifer
0
.4
U 0 0, q

a o"

Shole

Figure 6. Diagram showing possible miode of entry of
/Z

airborne wastes to aquifer.

-20-

Naturally occurring salty.or mineralized water may be redis-
tribluted and may flow into fresh-water aquifers. This salt-

water intrusion, a man-induced pollutant, occurs when pumping

wells near the sea or near coastal bodies of salty water may

cause an inflow of salty water if the hydraulic head in the

fresh-water aquifer is depressed sufficiently to cause the

salty water to move toward the center of pumping, see Figure 7.

tand surface Pumped well

table

res wa er
1bcba F h t r
.0
Fresh water
... . .........

t
.................4

-7
isIATURAL CONDITIONS
SALT INTRUSION

Figure 7.

---...-..Along the coa.st and even inland where salty water

underlies freshwater aquifers, pumping and consequent reduction

in hydrostatic pressure in the freshwater aquifer may cause

the underlying salty water to move upward.

Where salt or brackish surface water is in contact with

a f reshwater aquifer along some reaches of the Delaware
River, as an example, it will enter the a Iquif'er if the head

of the freshwater is low enough to permit it. On the other

hand,if the fresh water head is high enough, there will be
F

a flow of freshwater out of the aquifer, and no salt water

-21-

will enter.

Under natural conditions the freshwater-saltwater

interface is usually stable with only very severe droughts

perhaps affecting the salt line. But man has created an

inbalance by pumping out water near the saltwater line and
W,

.building impermeable surfaces increasing surface runoff and

therefore decreasing.,groundwate-- recharge. Both of these

factors lessen the hydraulic pressure of the freshwater

allowing for the intrusionof saltwater into the aquifers.

The dredging activities in the Delaware River involving the

clearing and maintenance of.shipping channels and the construc-

tion and maintenance of harbor facilities also has a large

affect on the nature of the',?,aquifers, especially Raritan
Magothy"aquifer.

@in ce*the Raritan Magothy formation outcrops underneath

the-Delaware River the maintenance of a ship channel to a

depth of at least 40 feet can-cut.into the Raritan Magothy,

allowing river water and its pollutants to flow unimpeded

into the aquifer. Also, the impact of dredging includes

placing of dredge spoils on the land where the aquifers

outcrop.

The quality of groundwater in the Coastal Zone has in

some areas been steadily decreasing due to contamination,

especially saltwater intrusion. No change is expected in

the future with the continuance of unrestricted pumping of

water and dumping of pollutants. Contamination of water

-22-

supplies of the heavily developed Coastal Zone is where salt

intrusion is most likely to:occur. It is possible that-in

the future some communities will not be able to meet their

own water demand. Proposed sludge landfill sites and continued

hazard dumping of chemicals will pose other groundwater

problems. Therefore, the need exists for more careful

planning and management for our groundwater resources.

-23-

APPENDIX A
REGIONAL REPORTS

1. HUDSON RIVER

A. Essex County

Physical Characteristics

Groundwater in Essex County occurs in joints and frac-
tures in consolidated rocks o'f the Brunswick Formation and

in the voids of unconsolidated stritified drift deposits.

Rocks of the Brunswick__-Formation are the main source of

groundwater in Essex County. They are generally capable of

sustaining moderate to large yields to wells.

Except for hardness and-,local salt-water contamination
water from these rocks is accept@'abie' for consumption.

in the Newark area, salt water contamination has seriously

impaired the quality of groundwater and chloride concentration

are as high as 1,900 ppm-

Unconsolidated sediments of Pleistocene age mantle the

bedrock throughout much of Essex County. Water occurs under

water table and artesiam @conait,ions. Water table condition

occurs wheresand and gravel deposits are not covered by

clay, silt, or glacial till and are exposed at the surface.

They are commonly less than 20 feet thick and do not yield

large quantities of water. They arerecharged directly from

precipitation on the outcrop area. Artesian groundwater

occurs where sand-and gravel deposits have been covered by

-24-

lake or silt, or by glacial till. These deposits are largely

confined to theburied valley so they are not visible on the

surface and their regional extent and distribution are

therefore not readily apparent. They are recharged by

leakage through overlying confining beds and by precipitation

falling on outcrop areas outside Essex County. Some recharge

may also be derived from the underlying and adjacent Brunswick

Formation.

The average yield is 908 gpm which makes it the most

productive aquifer in Essex County.

Water ranges in hardness from 104 ppm to 212 ppm. Most

of the samples analyzed had sulfate concentration of 40 ppm

ate concentration of ppm
or less-, chloride -11 ppm and rri r

or less.

Analysis

Groundwater has high chloride concentrations in areas

of relatively heavy pumpage in eastern Newark adjacent to

Newark Bay and the Passaic River. Heavy groundwater with-

drawals have lowered the general water level in these areas,

reversing the natural.gradient between the ground and surface

water bodies, and have induced a flow of salt water from the

river and bay into the underlying water-bearing formations.

A probable contributing factor in salt-water intrusion is

the dre dging of ship canals in Newark Bay and the Passaic

River. In deepening these canals, semimpervious Recent and

-25-

Pleistocene sediments were removed which had acted as an

imperfect barrier-to the infiltration of salt-water.

The most highly developed part of the valley - fill:

aquifer system is in western Milburn and southwestern Living-

ston. Four well fields tapping the Pleistocene sand and

gravel are located in an area of less than 4 square miles.,

With such spacing of wells and continued heavy development

has, naturally, lowered water levels in the aquifer in

addition with reduction in the amount of available recharge

and extended dry periods, especially from 1961 to 1966.

The localized higher concentration of sulfate, chloride

and nitrate suggests a low-grqde pollution problem, probably

resulting from either sewage or@ -.,the use of chemical ferti@-

lizers in thearea.

B. Rahway Area

Physical Characteristics

The Rahway area occupies 67 square miles of the Pedmont

Plateau and Coastal Plain_@@-Zroundwater in the Rahway area

is stored in the glacial drift, Raritan Formation and the

Brunswick Shale.

Brunswick Shale yields water from fracture openings and
from pore spaces in the interbedded sandstone. The average
yield of wells is 75 gpm. Recharge to the Brunswick oc . curs
through the hydraulically continuous overlying drift. Both

-26-

water table and artesian conditions exist in the Brunswick

Shale. Artesian co nditions occur generally at depths greater

than 100 feet; water table conditions occur at shallower

depths. Groundwater is locally high in sulfate, dissolved

solids, and hardness. Brackish water is contained in the

Brunswick Shale along the tidal reach of the Rahaway River

and northward along the Arthur Kill.

The Raritan Formation overlies' the Brunswick in the

southeast corner of the arear-..@Ca'.hd covers about 9 square

miles. The Raritan Formation is a series of clays and sands

of about 100 feet in thickness in the outcrop area. The

average yield of wells is 96 gpm.- The quality of the water

is good for most uses with th6 exception of salt-water

encroachment adjacent to Arthur Kill.'

@Glacial drift mantles the Brunswick Shale and the

Raritan Formation and forms the land surface of the area.

The drift has an average thickness of about 25'feet. The

stratified drift filling the buried valley in Rayway is the

only important aquifer of Pleistocene age in the area. The

average yield is 370 gpm. An important function of glacia,l

drift is to absorb.,.-,,@stox-e,4-.,znd transmit water to the under-

lying shale wherever they are hydraulically connected.

The quality of water is good, however there is potential

threat of salt-water encroachment during extended dry periods

and high tides encroaching farthest inland.

-27-

Analysis

If additional large groundwater supplies are developed

in the Rahway area, existing supplies would probably be

reduced, and intrusion of salt-water could result. In the

Brunswick Shale, over development would greatly lower water

levels in the sourtheastern half of the area. To insure a

supply of fresh groundwater in the Brunswick Shale, wells

should be located where the piezom.etric surface is 20 feet

or more above sea level. Salt water would not be expected

,at depths of less than about 800 feet in such areas, however,

this should,be verified by test drilling prior to any addi-

tional large-scale development.

Further development of groundwater from the Raritan@,.,-

Formation is limited by the danger of salt-water intrusion.

The pumping of wells along the Arthur Kill, forced many

industries to obtain water from inland public-water supply

companies because of drawn in-salt-water. Further pumping

would fol low the salt-water intrusion path soutwestward from

Sewaren where the Raritan Formation is exposed to the Arthur

Kill.

Salt-water contamination can occur in the glacial drift

along the river banks during hLgh tide if withdrawal of

ground-water from stratifed drift and the Brunswick Shale

should lower groundwater levels below river level. River

water would, then, seep into the groundwater reservoir.

-28-

2. North Shore

@A. Monmouth County

Physical Characteristics

The principal aquifers underlying the county occur in

;the Raritan and Magothy Formations, the Englishtown Formation,
!the Wenonah Formation and Mount Laurel Sand, the Vincentown

:'Formation, and the Kirkwood Formation. They crop out in

!bands trending northeast-sou ,thwest and slope downward toward

@the southeast. Thickness, pumpage, and water-bearing char-

;acteristics of these aquifers are summarized in the table 4.

1958

Thickness Pumpage Water-Bearing
;'Aquifer .(feet) (mgd) Characteristi'Cs

Raritan and Magothy 2.5-70--_ 12.3 Most important aqui-

Formations fers. Yields range

from 100 to 1,400 gpm

to large-diameter wells.

Englishtown Formation 30-50 4.0 Average yield 25 gpm.

Maximum reported yield

640 gpm. Average yield

to lar ge-capacity wells

410 gpm.

-29-

Wenonah Formation and 30-50 .65 Considered a single aqu-

Mount Laurel Sand fer. Average yield 10

gpm. Maximum reported

yield 335 gpm.

Red Bank Sand 40 Yields range from 3 to

30 gVm to-domestic wells.

Vincetown Formation 50-110 Numerous domestic wells

tap this aquifer-yields

range from 10 to 50 gpm.

Kirkwood Formation 0-79 1,.5 Yields range from 15 to

1,200 gpm.

Analysis

Raritan and Magothy Formations may be in hydraulic

connection with the Atlantic Ocean and development could be

limited by the threat of salt-water encroachment. Studies

indicate that scilt-water is present in the oceanward extensions

of the aquifer, perhaps about 4 or 5 miles offshore prior to

large-scale development. Water samples from a test well

drilled about 20 miles south of Sea Girt indicated salt-

water contamination of the lower part of this aquifer.

Until the actual location of the salt water in the aquifer

to the east of the county is known, development should

proceed with extreme caution.

_30-

The area most favorable for additional development of the

Raritan and Magothy Formations probably is the wes.tern.part

of the county, where pumpage would aggravate the salt-water

problem less than-would the same intensity of development in

the eastern part of the county. Salt water probably is

advancing toward coastal parts of the county in response to

existing development. Incre ased development along the coast

would accelerate the rate of advancement toward the coast

much more than would the same intensity of development in

..the western part of the county. Jersey Central Power and

Light has wells on Coniskunk Point which originally were

fresh water but have turned salty. The Village of Keyport

placed their production wells too close to the ocean and

they are now very high in chlorine.;- The area most favorable

for additional development of the Englishtown Formation and

Mount Laurel Sand is locally in the vicinity of their outcrop

areas southwest of the Sandy Hook Bay where water levels.are

highest and the threat of salt-water encroachment is less.

A number of the municipalities in northeastern Monmouth

County have been grante d diversion rights for wells in the

Englishtown Formation which far exceed the ability of this

formation to replenish itself in-the area of greatest use.

Newer wells are going to deeper formations with the same

situation occurring, if not properly controlled.

The Red Bank Sand may not be practical toattempt to

develop large-yield wells from this aquifer. However, wells

located near streams or ponds that are in hydraulic connection

with the aquifer may permit large yields, assumin g-that the

-31-

streams or ponds are free of contamination.

Probable favorable additional development in the aquifer

of the Vincentown Formation occurs locally in the vicinity

of the outcrop area and away ftom the Atlantic Ocean.

The Kirkwood Formations underlies about 25 percent of

-Monmou-L-.h County and makes up the principal water-table

aquifer in the southeastern part of the county. Favorable

additional development in areas where its saturated thickness

is at least 30-feet and remote from saline surface-water

bodies.

@The hydraulic characteristics of the suboceanic extensions

of thete aquifers have a greater influence on aquifer response

to pumping near the coast than to pumping inland from the

coast. Because much of the heavy pumping is along the

coast, the lack of information of conditions off shore is

unfortunate.

B. Middlesex County

Physical Characteristics

Of the various aquifers within the county three are of

major importance. The rocks of the Newark group are the

principal source of ground water in the northwestern part of

the co unty. The Old Bridge and Farrington Sands, both

-32-

members of the Raritan formation are the principal sources

of water supply in the southeastern two-thirds of the county.

The other aquifers are of relatively little importance

either because of the limited area in which they are available

or because they are not capable of yielding substantial

supplies.

The Old Bridge Sand crops out or is exposed beneath

permeable Pleistocene deposits in an irregular band that

extends from the Raritan Bay near South Amboy to and prob-
ably beyond Jamesburg. The thickness range from 80 to 110

feet. The dip of the sand is variable but it averages

approximately 40 to 45 feet per mile to the southeast. The

water from the Old Bridge sand is-excellent for most uses.

Iron removal plants have been installed by a number of the

larger users of water from this sand.

The Farrington sand occurs both north and south of the

Raritan Rivet and probably across the Arthur Kill on Staten

Island. It crops out in a conspicuous band nearly a mile

wide along the southeast edge of Farrington Lake where

several sand pits give a good opportunity to examine it.

The full thickness of the sand dips to the southeast at the

rate of about 55 feet per@mile. The uncontaminated water

from the Farrington sand is exceptionally-good for most

purposes.- The only feature of this water that is sometimes

objectionable in its iron content.

The Triassic rocks in New Jersey belong to the Newark

-33-

group which is divided into three formations: Stockton

formation, the Lockdtong formation and the@Brunswick formation.

All the sedimentary rocks of the Newark group dip to the

northwest at angles of 50 to 15P. With the exception of the

water that are contaminated by the intrusion of sea water,

the water from the Newark group is more highly mineralized

than any other groundwater obtained in Middlesex County.

Thie -w,.a-te.,r..i,s,high in,-calcium and magnesuim and the hardne,ss

is therefore high. Also there are high quantities of iron.

Analysis

There appears to be danger of salt-water intrusion into

the Old Bridge Sand at two p''.Ants. At the South Amboy Water
Works where the Sand is exposed 'to salt water in the Raritan

Bay and in the vicinity of Old Bridge where salt or brackish

water in the South River comes in contact wi th its intake

area., There is no widespread salt-water encroachment problem

in this aquifer yet, however,,,the.intensity and distribution

pumping has been limited by the threat of such encroachment.

In the vicinity of Parlin there are areas in which the Old

Bridge sand has been contaminated by industrial wastes.

Widespread salt-water encroachment in the Farrington

Sand Member has caused numerous wells to be abandoned. The

three principal places where salt water has entered the

Farrington Sand are near the confluence of the South River

and the Washington Canal, about a mile downstream from the

confluence of the Washington Canal and thQ Raritan River,

-34-

and near the mouth of the Raritan River.. The greatest

advance of salt water has been in the area south of Parlin.

If not restricted, the encroachment of salt,water threatens

to render a considerable part of this aquifer unfit for use

in most of the area south of Parlin. There is overpumpage

and the salt-water encroachment problem in the Runyon well

field.

.Industrial pollution around Runyon and pollution from

land fills in the South Brunswick vicinity as well as isolated

cases of septic system pollution are the threads of further

degradation of water quality in the Middlesex County.

.3. @eCentral Shore

A. Ocean County

Physical Characteristics

Ground water in Ocean County is obtained principally

from four artesian aquifer systems and a water-table aquifer.

The artesian aquifers in ascending stratigraphic order are:

the Rarita.n. a.nd Mago.#@_ r__Tozrmat ions,' the Englishtown Formation,

the Wenonah Formation and Mount Laurel Sand, and the Kirkwood

Formation.

The Raritan and Magothy Formations of Cretaceous age

form an artesian aquifer system 600 to 2,000 feet thick.
Well yield of 500 to 1,000 gpm (gallons per minute) can be

-35-

expected, but yields as high as 1,850 gpm have been obtained.

Recharge to the aquifers occurs from precipitation, mainly
'in the high level intake area from Trenton northeast to

Metuchen in northern Middlesex Counties. Potable water in

the aquifer system is soft (28 to 51 ppm hardness) and is

generally high in iron content (0.66 to 3.2 ppm). Temperatures

of 700 to 90OF make the water less desirable than shallow

water for cooling purposes. In the southern part of the

county, saline water is contained below 2,500 feet in depth

in the Raritan and Magothy Formations,'so wells approaching

this depth may include saline water. The salt water-fresh

water interface zone in the Raritan and Magothy Formations

trends through the Island Beach State Park area.

The aquifer in the Englishto'wn Formation produces-

maximum well yields of less than 500 gpm, and the average is

260 gpm. Recharge to the formation occurs predominantly

from'vertical leakage down through the overlying younger
formations in the topographic high areas,of Monmouth and

Camden Counties, 5 to 10 miles southeas t of the Englishtown

outcrop area. Water from the Englishtown Formation is soft

to moderately hard (30 to 82 ppm hardness and the pH ranges

from 7.5 to 8.3. The aquifer thins to.the southeast and is

absent in southern Ocean County.

The aquifer of the Wenonah Formation and Mount Laurel

Sand yields small quantities of water to wells (less than
10O.gpm) and is relatively undeveloped in northern Ocean
County, however is capable of further development. The

-36-

Aquifers: U, undifferentiated water-table aquifer; K. aquifer in the Kirkwoo

V, aquifer in the Vincentown formation; W, aquifer in the Wenonah

and Mount Laurel Sand; E,, aquifer in the Englishtown Formation; R,

the Raritan and Magothy Formations.

Area Aquifer Availability of ground wa

1. Summer Coastal Resort /K yields as much as 500 gpm.

ly. Potential'sea-water i
supp
levels are below sea ievel. S

mgd. R and contain saline wat

V are absent.

2. Undeveloped Pine Barrens R,K.U R, yields as much as 2,000 gpn

water in southern part of aree

less than in Area 1. Water lc

high in iron content U, yields

gpm possible. Water may be hi

acidic and odoriferous. E. W

3. Urban R,t,W,K,U R, same as in area 2. Pumpag

yields up to 500 gpm. Highly

e,, mgd. Sea-water intrusion

levels have declined as much

yields less than 100 gpm. Re

Pumpage less than 1 mgd. K,

hundred gpm. U, same as in a

CO 4. Rural R.-E.W,V,K,U Small amounts pumped for dome
I
W yields up to several hundre

Table 3 Summary of availability of ground water in Oce

water is generally soft. It contains high iron concentrations

locally. Downdip, the Wenonak Formation and Mount Laurel

Sand becomes a confining bed.

The Kirkwood Formation in Ocean County has wells that

yields as much as 1,225 gpm, but the average is about 420

gpm. Recharge to the Kirkwood Formation occurs in the

-topagr--aphic --hi-gh -are-a-s -of th-e inner @Caasta.l Plain by vertical.

leakage from the overlying water-table aquifer. Water from

the aquifer in the Kirkwood Formation is suitable for most

uses but may require treatment for removal of iron'. It is

generally soft to moderately hard (2.9 to 105 ppm hardness)

and generally low in dissolved solid content (4 to 180 ppm).

The water-table aquifer yields up to 600 gpm. In the

sparsely settled Pine Barrens, 0.8 mgd per square mile theo-

,rectically can be withdrawn from the aquifer without depleting

the storage. Water from the water-table,aquifer has a low

pH (4.4 to 6.7), high iron con-tent (.0.09 to 22 ppm), and an

unpleasant odor. Near Barnegat Bay and on. the barrier

beach., the aquifer contains brackish water.

The Vincentown Formation which is tapped locally in the

northwestern part of Ocean County.for domestic supply could

yield water in quantity to large - diameter wells near the
outcrop area. Elsewhere, it offers little potential for

further development.

_39-

The Manasquan Formation is generally considered an

aquitard, but it yields up to 500 gpm to wells along the

coast. This formation can be tapped further in Ocean County

for small to moderate water supplies.

Analysis

Artesian aquifers of the Raritan and Magothy, Englishtown,

Wenonah and Mount Laurel, and Kirkwood Formations and the

water-table aquifer supply the present water needs of Ocean

County. 0-[' these, the Raritan and Magothy and the water-

table aquifer are the largest and least utilized ground-

water reservoirs in the county and are the most suitable for

future large-scale development, however in the southern

third of Ocean County, all aquifers in the Raritan and

Magothy Formations probably contain water.

The aquifer in the Englishtown Formation is heavily

pumped in northeastern Ocean County. In this area, water

levels in wells have declined from above sea level to more

than 75 feet below sea level since 1900, however, there is

no evidence that the sea water has intruded the aquifer.

The Kirkwood Formation is the most heavily pumped aquifers

on the New Jersey coast south of Monmouth County. Since

1900, water levels in wells tapping this aquifer have declined

to as much as 30 feet below sea level on Long Beach Island.

In the Point Pleasant area where the Kirkwood crops out,

salt water was found there.

-40-

The water-table aquifer is pumped heavily in the Toms

River and Lakehurst areas. -Further development of wells to

maximum capacity will substantially diminish the flow of

Toms River. Ground water pollution in this aquifer occurs

from dumping of chemicals. The Pleasant Plains incident had

caused closing of 150 domestic wells.

-41-

4. South Shore

A. Cape May County

Physical Characteristics

Thre e main aquifers yield fresh water in Cape May

county; they are the unconfined Holly Beach water-bearing

zone, the Cohansey Sand, and the Kirkwood Formation.

The Cohansey Sand is the most productive aquifer in

Cape May County. It crops out along the Maurice River in

Cumberland County and north of the Tuckahoe and Great Egg

Harbor Rivers in'Atlantic County The principal high-level

recharge area for the Cohansey Sand is not in the outcrop

area but in the Belleplain area,of Cape May County and is

recharged by vertical leakage from the.overlying Pleistocene

sediments.

---.-Water from wells tapping the Cohansey Sand have a low
pH and are corrosive in the-Wo6dbine area. In. the lower

peninsular area of Cape May County, the enc roachment of salt

water has impaired the quality of water in the aquifer.

The Kirkwood Formation represents a thick section of

marine sand and clay beneath the Cohansey Sand. The formation

contains two confined water-bearing zones. The top of the

upper aquifer-Rio Grande water-bearing zone occurs from 260

feet below mean sea level in the northwestern part of the

county to about 600 feet below mean sea level in the southeast

at Wildwood, and the zone is on the average 50 feet thick.

-42-

The lower aquifer on Atlantic City "800-foot" sand is more

widely used and has a greater potential than the upper

aquifer. South of Wildwood it contains water of high chloride

concentration--more than 250 parts per million-and relatively

high dissolved solid content. Yields of between 500 to 800
gpm are common from the- Atlantic City "800-foot".sand. The

major source of recharge to the aquifers in the Kirkwood

Formation is precipation in the outcrop area.. The areal

extent of the outcrop of the Kirkwood Formation extends for

about 250 square miles from Gloucester to Monmouth Counties.

The aquifer most suitable for future development is the

shallow unconfined Holly Beach water-bearing zone. It is

recharged by direct percolation to the water. table. The

Holly Beach water-bearing zone crops out in Cape May County

in an area of about 160 square miles, excluding the land

area of the barrier bar from Ocean City to Wildwood and.

other tidal-march areas. In-the lower peninsular area of

Cape'May County, there is no chance for a build-up of fresh-

water head in the aquifer to prevent the salt-water interface

from moving inland. The construction of wells near a lake

or river where there is a known hydraulic connection with

the aquifer affords the opportunity to develop a large-
capacity supply by inducing in"'filtration of surface water.

The water is slightly acidic and high in iron.

Analysis

The heavy development of the Cohansey Sand on the Cape

May peninsula has lowered the water table*below sea level in

-43-

places. This has reversed the vertical and horizontal

hydraulic gradients on the lower peninsula. Wateris-now

moving to the centers of withdrawal at Rio Grande and Cape

May Formation.

The withdrawals from the Atlantic City "800-foot" sand

in Atlantic and Cape May Counties have reversed the hydraulic

'gr'ad-ient -,and -s-tarted -a, landward -mkgr-a-tIon of :salt water f rom

the ocean. The deterioration of water quality in the Kirkwood

Formation in the lower peninsular area of.Cape May County is

the result of salt-water encroachment caused by withdrawals

from the aquifers.

The major problem dealing with future development of

the Holly Beach water-bearing zone is the danger of salt-

water encroachment.* During severe subtropical or hurricane-

type storms, salt sprey is driven appreciable distances

inland in Ca.pe.May County. Salt-water flooding in areas of

low elevation during these storms is the severe and devas-

tating type of po llution. Other localized sources of pol-

lution includes refuse disposal sites, septic tanks.

The Cape May Canal, which'was constructed as a war-time

measure during the 1940's, has lowered the water table about

12 feet in the center of the county and released several

billion gallons of fresh water from groundwater storage.

The canal created an island at the top of Cape May County

and increased the danger of salt-water encroachment into the

unconfined aquifer.

-44-

5. Delaware Bay

A. Cumberland County

Physical Characteristics

Almost all water supplies in Cumberland County are

obtained from wells tapping.shallow groundwater supplies.

Most -,wells ob@tain_watex from the CohanseynKirkwood aquifer.

Successively deeper aquifers occur in the lower part of the

Kirkwood Formation, in the Piney Point Formation, in the

Wenonah Formation and Mount Laurel Sand, and in the Potomac

Group and Magothy-and Raritan Formations. Each of these

aquifers are separated by confining or semiconfining clay

.layers of varying thicknesses and permeabilities.

The Cohansey-Kirkwood aquifer has its recharge area in

the uplands in the northern part of the county and its main

discharge areas.are in the.eroded stream valleys and tidal

.march areas along Delaware Bay---.The groundwater in the

Cohansey-Kirkwood aquifer generally is low in dissolved

solids, less than .100 mg/l,.has a low pH (4.2 to 7.0), and

is usually corrosive. The water locally contains objection-

able concentrations of iron (up to 15 mg/1), and nitrate (up

to 65 mg/1).

The second most important source of groundwater in

Cumberland County is the lower Kirkwood aquifer. Most

recharge to the lower Kirkwood aquifer probably comes from

-45-

vertical leakage from the overlying Cohansey-Kirdwood aquifer

in the western part of the cou nty. The quality of water in

this aquifer along the Maurice River and Delaware Bay indicates

-that the potential-for salt-water intrusion is minimal under

present rates in Cumberland County.

The Piney Poin t Formation, underlying the-Kirkwood

Formation, is a minor aquifer in Cumberland County.

'The aquifer in the Wenonah Formation and Mount Laurel

Sand offers a potential source of additional freshwater

supplies in Northern Cumberland County. This aquifer is not

presently utilized in the county, however, because adequate

supplies are available from much shallower aquifers. Water

quality in the-northern part of the county, where water

levels in the.-Wenonah-Mount Laurel aquifer are well above

sea level, is very good as indicated by analysis of ground

water in nearby Salem County. The water becomes more salty

toward Delaware Bay.

Aquifers in the Potomac-Raritan-Magothy sequence contain

saline water and are not currently utilized in Cumberland

County.

Analysis

Groundwater supplies have b*een contaminated in a few

areas in the county largely as-a result of the leaching of

agricultural fertilizers and the improper disposal of indus-

-46-

trial wastes and domestic sewage. Practices and processes

that lead to contamination of groundwater supplie s are:

poorly managed landfill and excavation operations; leakage

of soluble sewage wastes from cesspools and septic tanks.

Contamination problems have been reported in several shallow

wells from several of-these sources in.Cumberland County.

Sa.lt-water intrusion may occur seasonably,in low-lying

areas where shallow aquifers are hydraulically connected to

Delaware Bay or other salt-water estuaries. Because of

greater groundwater levels from pumpage in summer than in

winter, water quality in many shallow wells near the tidal

portions of Cohansey and Maurice River probably deteriorates

seasonally. For such areas groundwater diversions must be

carefully monitored to,avoid damage to the water supply."o-,

Potential minor intrusion problems have occurred seasonally

in centers of pumpage near the Greenwich and the Port Norris

areas and along other tidal lowlands near Delaware Bay-

B. Salem County

Physical Characteristics

The important aquifers in the Salem County occur in the

Potomac Group and Raritan and Magothy Formations, Wenonah

Formation and Mount Laurel Sand, Vincentown Formation,

Cohansey Sand, and Cape-May Formation. Separating these

aquifers are aquicludes composed of clayey materials.

-47-

The Potomac Group and Raritan and Magothy Formations

contain the most productive aquifers in Salem County. They

crop out in Salem.County adjacent to the Delaware River in a

19-square mile triangular area that has a maximum width of 3

miles. These units underlie approximately 24 square miles

of the Delaware River and extend southwesterly into the

State of Delaware. In New Jersey, they dip to the southeast.

The combined thickness of these formations in Salem-County

ranges from 200 feet in the outcrop area to about 1, 000 feet

or more downdip. Reported 3n@elds of wells tapping these

aquifers range up to 360 gpm. The highest yields commonly

occur where the system has direct hydraulic connection with
the overlying Cape May Formation near the Delawa;e River.

Chemical analysis indicate- at most of the water from parts

of the aqui fer not contaminated by salt water is of good-,

chemical quality.

The aquifer in the W@nonah Formation and Mount Laurel

Sand is the second most highly used aquifer in.Salem County
and is an important source of water for future development.

Ground-water recharge to this aquifer in Salem County,
downdip from the outcrop, is derived mainly from vertical

leakage from over lying _,aqu�fers. The combined breadth of

outcrop for the two formations varies from 1 to 3 miles in

Salem County, and their-total thickness is not believed to
exceed 120 feet. Reported yields of wells range up to 507
gpm. Water from this aquifer ranges from soft to very hard
and is commonly high in iron. Salt-water intrusion, probabW

-48-

from the overlying Vincentown Formation in the vicinity of

the City of Salem is indicated by chloride concentrations up

to 396 ppm.

The aquifer in the Vincentown Formation is an important

aquifer in part of. Salem County. It is capable of supplying

considerably more water than is now being pumped and hence'

is -an -important -..source f or future .,groundwater. development.

Reported -yields of wells tapping this aquifer range up to
270 gpm. The water is hard lriid is moderate to high in iron

content. Salt-water intrusion is indicated by chloride

concentrations of up to 2,850 ppm.

-The Cohansey Sand, whitl@`unde rlies about 25 percent of

Salem County is composed of highly permeable materials and

hence is capable of transmitting large quantities of water.

It is an important source for future groundwater development.

It-is rechared by precipitation on its outcrop area. The

formation ranges in thickness. from less than 1, foot near the

western edge of its outcrop area to a known 82 feet and a

possible 200 feet in the extreme eastern part of the county.

Water in the aquifer is generally soft and slightly mineral-

ized. However, iron and d-i-s-solved carbon dioxide are commonly

present in objectionable quantities.

The Cape May Formation of Pleistocene age is an important
aquifer in the Penns Grove-Deepwater area where it yields up
to 1,500 . gpm to Ranney collector wells. The Cape May For7
mation crops out adjacent to.the Delaware River and its

.-49-

tributary streams and underlies about 85 square miles of

Salem County. The formation is as much as 150 feet thick in

the southwest and about 30 feet thick along streams in the

interior of the county. Where Pleistocene deposits are not
thick enough to' function.as an aquifer their chief hydrologic

function is to absorb precepitation and transmit it to

underlying formations.

Fine silt and clay of Holocene'age occur in tidal flats
and stream channels in Sale4hcounty. Along the Delaware

River and its tributaries these relatively impermeable

materials retard the movement of saline surface water into

the water-bearing sands of the underlying materials.

Analysis

A decline in water levels in the aquifers of the Potomac,

Raritan, and Magothy has resulted from heavy pumpage from

this aquifer system. This pumpage has significantly modified

the natural pattern of.ground-water movement in the system.

Whereas groundwater discharge was originally to the Delaware

River and its tributory streams, it is now to centers of

pumpage. Movement -o-f-va@@ -:.-toward centers of pumpage has

created the danger of salt-water encroachment into the

aquifer from the Delaware River and its tributar ies as well

as from downdip areas where the aquifer already contains
saline water. The occurence of saline water in the aquifer-
is indicated by chloride concentrations in the Salem Area

and at Carneys Point. Several small areas.of salt-water

_50-

encroachment from the Delaware River have been developed in,

the Deepwater area. This does not represent a massive

incursion of salt water into the aquifer but indicates that

river water has access to the aquifer. The layer of silt

and organic muck in the bed of the Delaware River and in the

tidal parts of tributaries tothe Delaware limits the rate

at which salt water can enter an aquifer. Therefore,-it is

extremely important,not toremove significant thickness of

these protective materials.

Salt water may intrude the Cape May Formation along the

Delaware River and along tidal reaches of its tributary

streams if the fresh-water head in the aquiferis lowered

sufficiently near-places where the Delaware River and the

Cape May Fo rmation are hydraulically connected. Because

water from the Cape May Formation recharges the older forma-

'tions, water of poor quality entering the Cape May Formation

could harm the underlying productive aquifer. Future gro und-

water withdrawals along the Delaware River should proceed

with care to avert further expansion of those areas in which

salt-water encroachment has taken place and to prevent

establishment of new areas of encroachment.

6. Delaware River Water Front

A. Gloucester County

Physical Characteristics

There are four aquifers where moderate to large amounts

of water can be pumped economically. They are: Raritan and

Magothy Formations, the Cohansey Sand, and the Wenonah

Formation and Mount taurel Sand.

The Most important and productive aquifer is the Raritan

and MagothyFormations. The aquifer yields about 75 percent

of the groundwater used in the county. Wells yield up to

1,400 gpm and large capacity wells usually can be drilled

almost anywhere in the county, however high chlorides maybe

present in the southeastern parts of the county.

The Raritan and Magothy Formations crop out'in a belt

0.2 to 3.2 miles wide adjacent.to the Delaware River and

cover about 32 square miles of surface area in the county.

The formations underlie the Delaware River and also crop out

in Pennsylvania.

in the outcrop area two water-bearing zones are identified.

The upper zone, usually artesian, includes the water-bearing

beds in the upper 120 feet of the Raritan and Magothy For-

mations. The.lower zone is always artesian in Gloucester

County and is composed of the water-bearing beds in the

lower 20 0 feet of the formations.

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The Cohansey Sand is the second*most important aquifer

in the county and has the greatest potential for future

development., The formation crops out of about 150 square

miles in the sparsely populated southern half of the county

and yields of 800 gpm are possible from wells less than 200

feet deep. The Cohansey Sand dips about 11 feet per mile

and ra-ncj-es in- thickness f rom. a f ew f-eet I-n -the outcrop area

to 130 feet at Newfield. Recharge to the Cohansey Sand is

from precipitation on the outcrop area and groundwater

movement is effected to some extent by the topography. From

the high-level intake area near Gross Keys some groundwater

moves south and discharges into the Great Egg Harbor River

and some moves west and discharges into the Maurice River or
its tri@utaries.

@The most undesirable feature of the water in this

formation is the iron content for which the water must be

treated

The Wenonah Formati on and Mount Laurel Sand are capable

,of yielding 100 to 200 gpm to wells in the area between

Pitman and Turnersville. The outcrop ranges in width from

0.3 to 3.0 miles and covers about 300 square miles. The

combined thickness of the two formations in the county

ranges from less than 65 to 95 feet.

d:.
The 'Wenonah Formation and Mount Laurel Sand is recharge@'

mostly by leakage through the overlying formation. No

-53-

single chemical analysis may be considered typical of water.

from these formations. Locally, two miles east of Wenonah,

in the outcrop area well yields water that contains more

than 100 mg/1 each of chloride and nitrate.

Analysis

of water,-in the Raxitan and Magothy Formation

is influenced by the quality of the Delaware River water.

The Delaware River probably is as important a source of

recharge as is precipitation on the outcrop area;'-therefore,

the quality of the river,water is of prime importance.

During periods of low flow, river water of poor quality is

more likely to recharge the aquifers. If preventative

measures to maintain low-chloride concentrations in the

river are not adequate, the groundwater supplies along the

lower reaches of the Delaware River, will be the first

affected. Also, the movement of groundwater is influenced

by the areas of heavy industrial pumping on both sides of

the Delaware River.

The Cohansey Sand in the county is almost undeveloped

and is an extremely important potential source of large

groundwater supplies, however, anylarge-scale pumping from

the Cohansey Sand may decrease the flow of the main streams,

such as Great Eag Harbor and Maurice River and in turn may

allow increased upstream movement of saline water in the

tidal reaches of the stream in Atlantic and and Cumberland

Counties.

-54-

The high localized nitrate content.in the Wenonah.

formation and Mount Laurel Sand indicated local pollution

probable due to leached animal wastes or fertilizers.

Pollution of this type is not uncommon in farming and rural

areas.

B. Camden

Physical Characteristics..,,;...

The physical characteri'stics of aquifers in Camden

County are similar to Gloucester.County aquifers.

Analysi

Areas of heavy pumping in or near the intake areas o*f

the Raritan and Magothy aquifers reversed the normal flow

pattern, so that induced recharge from bodies of surface

water mainly from the Delaware Riv er, now supplies much of

the water drawn from wells. The water in the Delaware River

upstream from Camden has generally been of satisfactory

quality for rechargi-ng the-a@ifers, and along this reach of

the river the quality of the groundwater has not been affected

adversely by' induced recharge. In some places downstream

from Camden, the river water is more highly mineralized due

partly to pollution by the disposal of wastes or by a com-

bination of waste disposal and induced recharge from highly
mineralized sources in Philadelphia and Camden, but mainly

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to the advance of salt water up the channel from the Atlantic

Ocean. Induced recharge from the river in such places.

adversely affects the quality of the groundwater. Thus, for

this aquifer the protection of aquifer recharge area, though
important, is less import antthan protecting Delaware'River

water quality.

-56-

APPENDIX B.
so RCES

SOURCES

Anderson, Henry R. And Appe 1, Charles A., Special Report

No. 29: Geolo5y and Groundwater Resources of Ocean New

Jersey Department of Conservation and Development,

1969.

2. Anderson, Henry R., "Geology and Groundwater'Re sources of

the.Rahway Area New Jersey". Special Report No. 27

USGS and New Jersey Department of Conservation and

Economic Development, 1968.

3. Appel, Charles A. "Salt-Water Encroachment Into Aquifers

of the Raritan Formation in the Sayerville Area, Middle-

sex County New Jersey"; USG.S and New Jersey Department

of Conservation and,@Edonomid Development, 1962.

4. Baldwin, Helen L. "A Primer on Groundwater" United

.....@,Gtates Government Printing Office, Washington, 1963.

5. Barksdale, Henry C. And others; "The Groundwater Supplies

of Middlesex County New Jersey", USGS and State Water

Policy Commission, 1943.

6. Barksdale, Henry C. "Groundwater Resources in the Tri-

State Region adjacent to the Lower Delaware River" USGS

and States of New Jersey, Pennsylvania, and Delaware,

1958.

7. Caputo, Darryl; Hochman, Michael; Hougen, Stewart;

-57-

"Ecological Planning: Water Resources Study on the

Assunpink Water", M.S. Thesis, University of Pennsylvania,

1973.

8. De Camp, Stephen Telephone Communication, Aug Iust 20,

1976, Middlesex County Planning Board.

9. Ep-st-ein Sue, "Monmouth To OpenVater Study" The Star-

Ledger, July 20, 1976.

10. Gill,,Harold E. "Groundwater Resources of Cape May

County, New Jersey Department of Conservation and

Economic Development Special-Report 18, 1962.

11'. Goldman, Evans, Jenner, Lawrence III., Repaupo Creek

Watershed; Gloucester County, New Jersey: An Environ-

mental Planning Study". Master's-Thesis University of

--...Pennsylvania, 1974.

12. Hard, Hilton; "Water Resources and Geology of Gloucester

County, New Jersey" USGS and New Jersey Department of

Conservation and Economic Development, 1969.

13. H. A. Swenson and H. L. Baldwin; "A Primer on Water

Quality" United States Government Printing Office,

Washington, 1965.

14. Jablonski, Leo A._, Special Report No. 23: Groundwater

Re*s*ources of Monmouth County, New Jersey; Trenton,

-58-

Department of Conservation and Economic Development,

1968.

15. Johnson, Meredith E. and Wiibur, Charles P., The Geology

of New Jersey, Trenton, Department of Conservation and

Development, New Jersey, 1940.

16. Lazier, Jim, Telephone Communication August .11, 1976.

17. McCall, John E. Ground-vat&'-,r@-.'@ in New Jersey, Trenton,

USGS Unpublished paper.

18. Nichols, William D. "Groundwater Resources of Essex

County New Jersey" SpeciatReport No. 28, USGS and New
Jersey. Department of Conservation' and Economic Develop-

ment, 1968.

19-Pollock, Steve; Telephone communication August 20, 1976,

Ocean County Planning Board.

20. Pettyjohn, Wayne A. "Water Quality In A Stressed

Environment" Readings in Environmental Hydrology,

Burgess Publishi-ng.,@Ib=eapolis, 1972.

21. Rooney, James G. "Groundwater Resources, Cumberland

County", New Jersey Special Report No. 34, USGS and DEP

1971.

22. Rosenau, Lang, Hilton, Rooney; "Geology and Groundwater'
-59-

Resources of Salem County, New Jersey", Special Report

No. 33,'USGS and State of New Jersey Department of

Conservation and Economic Development 1969.

23. Rutherford, Dave;-Telephone Communication August 11,

1976.

24. Widmer, Kemble to Kinsey, David, "Conversation with

Mr.-Rivkin - Recharge Areas in-the Coastal Zone", 7

January 1976.

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