IDENTIFICATION AND CONTROL OF POLLUTION
FROM SALT WATER INTRUSION
UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
1973
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FOREWORD
Degradation of the quality of fresh surface and ground
waters by Intrusion of saline water Is a common and complex
problem 1n both coastal and Inland areas. Seldom 1s the
problem the direct result of waste disposal. More often 1t
1s the Inadvertent result of man's activities as he alters
his environment.
The Federal Water Pollution Control Act Amendments of
1972 require the Administrator of the Environmental Protection
Agency to Issue Information on Identification and control of
pollution from salt water Intrusion (subsection 304(e)(1&2)(E)).
This report 1s Issued pursuant to that legislative mandate.
Russell E. Train
Administrator
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EPA-430/9-73-013
IDENTIFICATION AND CONTROL OF
POLLUTION FROM SALT WATER INTRUSION
United States Environmental Protection Agency
Office of Air and Water Programs
Water Quality and Non-Point Source Control Division
Washington, D. C. 20460
1973
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 - Price $1.25
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CONTENTS
GUIDANCE FOR IDENTIFICATION
AND EVALUATION OF THE
NATURE_AND_EXTENT OF POLLUTION FROM SALT WATER INTRUSION
INTRODUCTION 1
CAUSES OF SALT WATER INTRUSION 3
Sea Water Intrusion in Coastal Aquifers 3
Upstream Encroachment of Sea Water 4
Intrusion in Inland Aquifers. 5
EXTENT OF POLLUTION FROM SALT WATER INTRUSION 6
IDENTIFICATION OF POLLUTION
FROM SALT WATER INTRUSION 7
EVALUATION OF THE EFFECTS OF
SALT WATER INTRUSION 15
Sources of Additional Information 19
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PART_II
PROCESSESr_PROCEDURES AND METHODS FOR CONTROL OF POLLUTION
FROM SALT WATER INTRUSION
INTRODUCTION 20
WATER QUALITY AND POLLUTION 22
Hydrogeological investigations 23
SEA WATER INTRUSION IN COASTAL AQUIFERS 25
Scope of the Problem 25
History 26
Intrusion in the United states 27
Environmental Consequences 28
Causal Factors 29
Pollutant Movement 30
Control Methods 32
Monitoring Procedures 40
References 42
UPSTREAM ENCROACHMENT OF SEA WATER 44
History and Scope of the Problem 44
Encroachment in the United States 45
ii
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Environmental Consequences 46
Causal Factors and Pollutant Movement 47
Control Methods 48
Monitoring Procedures 51
References 53
SALINE WATER IN INLAND AQUIFERS 54
Scope of the Problem 54
Intrusion in the United States 56
Environmental Consequences 57
Causal Factors 57
Pollutant Movement 64
Control Methods 65
Monitoring Procedures 70
References 71
INSTITUTIONAL AND LEGAL ASPECTS 73
The Federal Water Pollution control Act As Amended . . 73
Water Rights 73
Ground Water Basin Management 78
Concept 78
Procedure 80
sources of Basin Pollution 82
control Methods 83
Legal and Institutional Requirements 85
iii
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Social Problems and Goals 91
References 93
iv
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List _of Figures
No.
1. Schematic vertical cross section showing fresh water 32
and sea water circulations with a transition zone,
2. Control of sea water intrusion in a confined aquifer by 33
shifting pumping wells from (a) near the coast to (b)
an inland location, (Todd, 1959) .
3. Control of sea water intrusion by a line of recharge 35
well's to create a pressure ridge paralleling the coast,
(Todd, 1959) .
4. Control of sea water intrusion by a line of pumping 36
wells creating a trough paralleling the coast, (Todd,
1959) .
5. Control of sea water intrusion by a combination 37
injection-extraction barrier using parallel lines of
pumping and recharge wells, (after California
Department of Water Resources, 1966) .
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6. Control of sea water intrusion by construction of an 39
impermeable subsurface barrier, (after California
Department of Water Resources, 1966).
7. Schematic diagram of upconing of underlying saline 60
water to a pumping well.
8. Diagram showing upward migration of saline water caused 61
by lowering of water levels in a gaining stream,
(Deutsch, 1963) .
9. Diagram showing interformational leakage by vertical 62
movement of water through wells where the piezometric
surface lies above the water table, (after Deutsch,
1963) .
10. Illustrative sketch showing four mechanisms producing 63
saline water intrusion in Southern Alameda County
California, (after California Department of Water
Resources, 1960).
11. Monthly variations of total draft and chloride content 68
in a nearby observation well, Honolulu aquifer (after
Todd and Meyer, 1971).
vi
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GUIDANCE FOR IDENTIFICATION AND EVALUATION OF THE NATURE
INTRODUCTION
Section 30 U (e) of the Federal Water Pollution Control
Act as Amended 86 Statute 816; 33 U.S.C. 1314 (1972)
provides that:
"The Administrator {of EPA)... shall issue. . .within one
year after the effective date of this subsection (and
from time to time thereafter) information including (1)
guidelines for identifying and evaluating the nature
and extent of non-point sources of pollutants, and (2)
processes, procedures, and methods to control pollution
resulting from -...
(E) salt water intrusion resulting from reductions of
fresh water flow from any cause, including extraction
of ground water, irrigation, obstruction, and
diversion; . . .
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This document has been prepared by the United states
Environmental Protection Agency in response to the
requirements of Section 304 (e) (1) (E) of the Act.
The following sections contain informational guidelines
for identifying and evaluating the nature and extent of
pollution from salt water intrusion. The circumstances
surrounding local salt water intrusion problems vary widely
and a uniform "cook book" approach to problem identification
and evaluation is not possible. Accordingly, this guidance
is not intended to provide a step-by-step procedure for
field reconnaissance or sampling techniques. Knowledge of
the existence and delineation of the spatial distribution of
waters contaminated by salt water intrusion will serve
little useful purpose by itself. If salt water intrusion is
to be effectively controlled it must be understood and
evaluated in the context of the causal factors within the
drainage basin. The intent of these informational
guidelines is to provide a basic framework for assessment of
salt water intrusion problems and their relationship to the
total hydrologic system, and to aid State authorities in
developing areawide waste treatment management plans in
accordance with the provisions of Section 208 of the Federal
Water Pollution control Act as Amended.
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CAUSES QF SALT,WATER INTRUSION
Salt water intrusion whether into surface or ground
water is a complex situation controlled by the geologic and
hydrologic characteristics of the area. Natural water
systems are dynamic. They respond in quality and quantity
to natural phenomena and to man's activities such as changes
in land use, stream channel linings, and consumptive
withdrawal. Identification and evaluation of the nature and
extent of salt water intrusion begins with an understanding
of the general mechanisms by which intrusion occurs.
Sea Water Intrusion in coastal Aquifers
Under natural conditions fresh ground water in coastal
aquifers is discharged into the ocean at or seaward of the
coastline, A balance or equilibrium tends to become
established between the fresh ground water and the salt
water pressing in from the sea. Where coastal aquifers are
overpumped, lowered by natural drainage, or natural recharge
is impeded by construction or other activities, the ground
water level, whether water table in unconfined aquifers or
piezometric surface in confined aquifers, is lowered thereby
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reducing the fresh water flow to the ocean. The interface
between the fresh and saline water has a parabolic form with
the saline water tending to underride the less dense fresh
water. The reversal or reduction of fresh water flow allows
the heavier saline water to move into areas where only fresh
water previously existed. Thus, even with a seaward
pressure gradient, sea water can advance inland. Because of
the high salt content of sea water, as little as two percent
of it mixed with fresh ground water can make that portion of
the aquifer unusable in relation to the U.S. Public Health
Service drinking water standard for total dissolved solids.
Only a small amount of intrusion can have serious
implications regarding the future use of an aquifer as a
water supply source.
UpstreanLEncroachment of Sea Water
The interaction of river flow and tidal currents
results in a net upstream movement of sea water along the
bottom with fresh water overriding this wedge in a seaward
direction. The position of the interface between the fresh
water and the sea water is dependent on channel geometry,
river discharge, and high tide height. A change in any of
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these parameters will cause the salt water/fresh water
interface to migrate. The most common causes of upstream
encroachment of sea water are deepening of navigation
channels, construction of sea level canals, and reduction of
stream flow. Reduction of stream flow or deepening of
channels results in landward migration of the sea water
wedge while increased stream flow results in a seaward
migration. Sea water encroachment can contaminate both
surface and subsurface water supplies, render fish and
wildlife habitats unsuitable for native populations, and
through increased corrosion shorten the life expectancy of
engineering structures.
Intrusion in Inland Aquifers
Large quantities of saline water exist under diverse
geologic and hydrologic environments in the United States.
Most of the Nation's largest sources of fresh ground water
are in close proximity to natural bodies of saline ground
water. Interaquifer transfer of saline waters results from
two basic mechanisms. One involves the upward migration of
saline waters into fresh water aquifers as a result of man-
induced changes in the hydrologic pressure regime. The
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other involves the direct transfer of saline waters
vertically through wells or other penetrations. Because of
the relatively slow movement of ground water, any saline
water intrusion may produce detrimental effects on ground
water quality that could persist for months or years after
the intrusion has ceased.
Salt water intrusion problems are ubiquitous in coastal
areas and surprisingly widespread in inland areas. On the
highly populated Atlantic Coast, between Massachusetts and
Florida, each of the States has reported problems with sea
water intrusion. The seriousness of the problem is usually
dependent on the intensity of urban and industrial
development with its attendant withdrawal and non-return of
water .
On the West Coast, California has had many problems
with sea water intrusion and has spent considerable effort
trying to solve or ameliorate the problem. Approximately
two thirds of the conterminous United States are underlain
by saline waters containing more than 1,000 mg/1 dissolved
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solids, and the problem of salt water intrusion in inland
aquifers can be the same as in coastal areas. Only eight of
the fifty States do not report significant salt water
intrusion problems.
IDENTIFICATION_OF_POLLyrigN FROM SALT WATER INTRUSION
Most intrusion of salt water into fresh water can be
ascribed to one of three primary mechanisms: the reversal or
reduction of fresh water discharge which allows the heavier
saline water to move into an area where only fresh water
previously existed; the accidental or inadvertant
destruction of natural barriers that formerly separated
bodies of fresh and saline waters; or the accidental or
inadvertant results of the disposal of waste saline water.
Major elements in an assessment of the occurrence and
extent of salt water intrusion should include:
1. spatial delineation of primary aquifers and
streams,
2. analysis of historical water quality (salinity)
data for suspect areas, to establish trends.
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3. establishment of a salinity monitoring network for
surface and ground water,
4. monitoring the location of the fresh water/salt
water interface,
5. basin wide hydrogeologic investigations where
saline intrusion occurs to identify causal
factors.
Prime areas for consideration should include rapidly
developing coastal areas where demands for fresh water
result in a reduction or reversal of flow gradient; and
areas of coastal waterway or embayment construction, or
deepening of navigation channels where natural barriers to
salt water flow may be breached. Another prime example of
breaching of confining strata is encountered in drilling
operations, especially in oil producing areas where salt
water may move great distances along broken or corroded well
casings or improperly abandonded wells. Not to be
overlooked as a source of pollution is any operation that
disposes of waste saline waters, whether disposal is
directly to surface streams or to the ground water through
evaporation pits or other methods.
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In other than oil producing areas salt water intrusion
is seldom the direct result of waste disposal. More often
it is the natural adjustment of the hydrologic system to the
many stresses placed upon it. Fundamental to an evaluation
of the extent of salt water intrusion is the need for
comprehensive hydrogeological investigations of the surface
and subsurface water systems. Identification and evaluation
of the extent of salt water intrusion should be an integral
part of each State's water quality monitoring program
required under section 106 (e) (1) of the Act, with salinity
one of the parameters routinely monitored throughout the
water quality network.
As an initial step in the evaluation of the nature and
extent of salt water intrusion principal aquifers must be
spatially defined, and historical water quality records for
both surface and ground waters should be collected and
contour maps of salt concentration compiled. In this way,
natural or base line conditions can be established and the
location of the salt water/fresh water interface can be
displayed in relation to the water requirements of the
hydrologic basin. Updating of such maps from current
monitoring data provides a rapid indication of the advance
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or retreat of the salt water wedge. Under normal conditions
monitoring points should be measured for salinity (or total
dissolved solids) or checked for electrical conductivity at
one to two month intervals. More frequent measurements may
be warranted if encroachment is in the proximity of major
water supply sources.
Most salt water intrusion problems will be encountered
in heavily populated coastal areas. In many cases extensive
water quality monitoring programs will have been in effect
and will provide most or all of the water quality data
required for determining the present extent of salt water
intrusion in that area, salinity measurements of both
surface and ground waters should be an integral part of the
State's water quality monitoring program and form the basic
data input for continuous evaluation of the extent of salt
water intrusion.
An inventory of existing monitoring points for both
surface and ground waters which may be used in determining
the salinity of streams and principal aquifers should be
undertaken by each state, and additional monitoring stations
installed as part of the State's water quality monitoring
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network where necessary for adequate spatial coverage. In
situ measurement of electrical conductivity can provide an
indication of salt content in surface and ground waters
without collecting water samples for laboratory analysis.
Sampling information for each surface or subsurface
monitoring station should include:
1. location by latitude, longitude and elevation,
2. stream or aquifer identification and date,
3. depth or depths of samples,
4. stream velocity,
5. temperature,
6. electrical conductivity, TDS, or chloride concentration,
7. depth to water table.
Where a rise in electrical conductivity is noted,
samples should be analyzed for increased salinity.
Automatic recording devices can be installed for continuous
electrical conductivity monitoring, and should be
incorporated in the State's water quality monitoring
network. Any water samples that are taken for laboratory
analysis should be secured and preserved according to
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standard methods as described in Methods for Examination of
Water and Wastes. (U.S. Environmental Protection Agency,
1971).
where salt water intrusion in either surface or ground
water is suspected or know to exist, a comprehensive
hydrogeological investigation should be designed to provide
requisite information for planning and control programs.
The type of information that may be required could include:
1. the geologic structure of the surface and ground
water basins and their boundaries;
2. the nature and hydraulic characteristics of the
subsurface formations including:
a. rock type
b. degree and type of porosity
c. permeability
d. reservoir pressure
e. degree of hydraulic continuity with surface
waters.
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3. surface water and ground water levels, and
directions and rates of movement and seasonal
fluctuations;
1. surface water and ground water quality,
particularly natural chlorides content;
5. sources, locations, amounts, and quality of
natural recharge;
6. locations, amounts, and quality of artificial
recharge;
7. locations and amounts of extractions.
Historical information of this type is generally
available, to some degree, in published form from Federal,
State, and local agencies that are concerned with water
resources. Additional information of this type can be
derived from a variety of investigative techniques including
but not limited to:
1. geologic reconnaissance.
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2. geophysical surveys,
3. examination of well logs,
4. test holes,
5. well pumping tests,
6. measurement of surface and ground
water levels,
7. chemical analysis of samples of surface
and ground waters,
8. analysis of precipitation and runoff records.
Techniques for predicting the location and extent of
salt water intrusion mainly rely on mathematical analysis of
aquifer and stream parameters, and tidal characteristics.
The level of sophistication and predictive ability of
analytical techniques varies from simple extrapolation of
the time of arrival of the salt water/fresh water interface
at successive observation wells to highly complex numerical
models of the entire hydrologic system. Discussion of the
application of these techniques is beyond the scope of this
report but selected references to detailed explanations are
included at the end of this section.
1ft
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The areal extent and depth of detail of the
investigations will vary with the extent of the water basin
or aquifer that has been or may be affected, and the present
and prospective uses of the water resources. The
investigations should be designed to define the water budget
of the basin or aquifer in sufficient detail to allow
prediction of the volumes and rates of surface and ground
water flow necessary to arrest and reverse the salt water
advance. Such information will be an integral part of the
data base used in basin wide water use planning, management,
and pollution control programs.
EVALUATION_QF_THE_EFFECTS OF SALT WATER INTRUSION
As surface and ground waters are integral parts of the
same hydrologic whole, changes in the salinity concentration
of one will most likely affect the salinity concentration of
the other. If the objective of a salt water intrusion
control program is to maintain zero increase in the salinity
of fresh water resources, this objective is seldom
attainable especially in areas of high water use. Nor is it
possible to define a single optimal or tolerable salinity
concentration for "fresh waters". These concentrations are
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dependent on the use that is to be made of the water. Water
devoid of dissolved materials is intolerable in nature
because pure water will not support life. Natural waters
contain endless varieties of dissolved materials in
concentrations that differ widely from one locality to
another as well as from time to time. The chlorides,
sulfates, carbonates, and bicarbonates of sodium, potassium,
calcium, and magnesium are generally the most common salts
present. Different organisms vary in their optimum salinity
requirements as well as in their ability to live and thrive
under variations from the optimum.
Any evaluation of the potential effects of salt water
intrusion must be performed in the context of its effect on
the total dissolved solids of the receiving water and the
water use requirements.
Optimal and tolerable salinity concentrations will be
different for such uses as: public water supplies, fish and
wildlife production, and agricultural uses. Waters with
less than about 500 mg/1 total dissolved solids are
generally considered suitable for domestic purposes, while
waters with greater than about 5,000 mg/1 TDS generally are
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unsuitable for irrigation purposes. Maximum salinity
concentrations for livestock consumption vary from less than
3,000 mg/1 TDS for poultry to as much as 12,000 mg/1 TDS for
sheep. A more detailed analysis of salinity requirements
for various water uses is contained in Water Quality
Criteria. (U.S. Environmental Protection Agency, 1972).
Evaluation of the nature, extent and effects of salt
water intrusion may vary from simple plots of water quality
that indicate the position of the salt water/fresh water
interface to sophisticated mathematical models of the entire
surface and ground water basin. Such models can be used to
predict the response of the salinity concentration to
various types of stresses at any point in the system and
allow for long-range basin planning and comprehensive
intrusion control programs. The degree of sophistication of
analysis required will vary in proportion to the complexity
of the hydrologic system and the water demands for the area.
Regardless of the level of analysis involved the objective
of the water quality monitoring and hydrogeologic
investigations should always be to relate salt-water
intrusion to its causal factors. Only in this way can water
use planning be accomplished in a manner that will maintain
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the hydrologic balances necessary to control salt water
intrusion.
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Sources of Additional Information
1. Payers, F.J., and Sheldon, J.W. , 1962, "The Use of a
High Speed Digital computer in the Study of the
Hydrodynamics of Geologic Basins": Jour.. Geophys.
' V. 67, no. 6, p. 2421-2431.
2. Freeze, R.A. , 1971, "Three-dimensional, Transient,
Satur a ted-Un saturated Flow in a Ground Water Basin":
water Re sour. Res_.., v. 7, no. 2, p 347-366.
3. Freeze, R.A. , and Witherspoon, P. A., 1966-8,
"Theoretical Analysis of Regional Ground Water Flow":
Part 1, Water Resour . Res.. v. 2, no. 4, p. 641-656,
1966 Part 2, Water Resour. Res_.. v. 3, no. 2, p. 623-
634, 1967 Part 3, Water Resour. Res, v. 4, no. 3, p.
581-590, 1968
4. Ippen, Arthur T. , "Salt-Water Fresh-Water Relationships
in Tidal Channels", Proceedings of the Second Annual
American Water Resources Conference? 1966." ~
5. Kashef, Abdel-Azis, F. , "Model Studies of Salt Water
Intrusion", Water Resources Bulletin, Vol. 6, No. 6,
P944-967, 1970.
6. Pinder, George F., "A Numerical Technique for
Calculating the Transient Position of the Salt Water
Front", Water Resources Research, Vol. 6, No. 3, P 875-
882, 1970.
7. Pinder, G.F., and Frind, E.G., "Application of
Galerkin's Procedure to Aquifer Analysis": Water
B§§2!i£i Res^, V.8, no. 1, p. 108-120. 1972.
8. U.S. Environmental Protection Agency, Subsurface Water
Pollution - A Selective Annotated Bibliography - Part
II - Saline Water Intrusion, 1972. ~~
9. Witherspoon, P. A. , Javandel, I., and Neuman, S.P., Use
of the Finite Element Method in Solving Transient Flow
Problems in Aquifer Systems: p. 687-698 in The Use of
Analog and Digital Computers in Hydrology (vol. 2) :
Intemat. Assoc. Sci. Hydrol. Publ. No. 81. 1968.
19
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PPnPgSSESJ,_PRQCEDURES AND METHODS FOR CONTROL OF POLLUTION
FRQM_SALT WATER INTRUSION
INTRODUCTION
This information has been prepared by the United States
Environmental Protection Agency in response to the
requirements of section 304 (e) (2)(E) of the Federal water
Pollution Control Act as Amended 86 Statute 816; 33 U.S.C.
1314 (1972) . Discussed herein are processes, procedures,
and methods for control of pollution from salt water
intrusion. The purpose of this information is to provide a
basic framework for assessment of salt water intrusion
problems and their relation to the total hydrologic system,
and to aid state authorities in developing salt water
intrusion surveillance and control programs in accordance
with the provisions of the Act. The treatment of the topic
is not intended to be comprehensive or exhaustive, since
this would take many volumes. Rather, the intent is to be
as concise as possible, addressing those aspects felt to be
most important, with liberal use of selected references for
more detailed explanations. Revision, expansion, and more
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detailed treatment of selected aspects of salt water
intrusion control will be accomplished under the provisions
of the Act that require periodic updating of such
information.
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U ALI TY AND POLLUTI ON
The quality of water refers to its chemical, physical,
and biological characteristics. All naturally occurring
waters contain dissolved mineral constituents, all possess
characteristics such as temperature, taste, and odor, and
some contain organisms such as bacteria. The natural
quality of water depends upon its environment, movement, and
source. For the purposes of this report, pollution is
defined as the man-induced degradation of the natural
quality of water. The particular use to which water can be
placed depends, of course, upon its quality. However, the
various criteria defining the suitability of a water for
municipal, industrial or agricultural use are not considered
in describing pollution. Instead, the measure of pollution
is a detrimental change in the given natural quality of
water. This may take the form, for example, of an increase
in chloride content, of a rise in temperature, or of the
addition of E. coli bacteria.
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Hvdroqeological Investigations
A fundamental concept applicable to almost all water
pollution control situations and inherent in all of the
processes, procedures, and methods for control of salt water
intrusion discussed in this report is the need for
comprehensive hydrogeological investigations before initia-
ting control procedures. The geologic and hydrologic
environment of each water resource system is unique. Ground
water systems are far more complex and slower reacting than
surface water systems.
Water resource systems are dynamic in nature. Surface
and ground water resources are integral parts of the same
hydrogeological whole. They respond both in quantity and
quality to natural phenomena and to man's activities
including changes in land use, stream channel lining, and
artificial recharge. Quality changes result from a variety
of causes of which waste discharge is only one.
Developed ground water systems are subject to both
seasonal changes and long term trends. In the case of salt
water intrusion, pollution may not be the result of waste
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discharge but rather the natural response of the hydrologic
system to the various stresses placed upon it. Because of
the dynamic nature of water resource systems, the historic
behavior of the systems involved must be studied as well as
future responses to anticipated changes in man's influences.
The longer the period and the more extensive the available
records, the better will be the evaluation of the system.
For stressed systems, continuing data collection and
periodic reevaluations are essential for the eventual
elimination of pollution. Regardless of the level of
sophistication of analysis required the objective of the
hydrologic investigations should always be to relate salt
water intrusion to its causal factors.
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SEA_WATER_INTRUSION_IN_COASTAL_AQUIFERS
Scope of the Problem
Under natural conditions fresh ground water in coastal
aquifers is discharged into the ocean at or seaward of the
coastline. If, however, demands by man for ground water
become sufficiently large, the seaward flow of ground water
is decreased or even reversed. This allows the sea water to
advance inland within the aquifer, thereby producing sea
water intrusion.
This section briefly describes the history of sea water
intrusion; occurrence of such intrusion in the United
states, and the environmental consequences, causal factors,
and movement of sea water in the underground. Thereafter,
control methods and monitoring procedures are presented,
together with references to sources of additional
information.
Emphasis in this section is on control of the lateral
movement of sea water underground, control of vertical flow
mechanisms causing intrusion are presented subsequently.
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Sea water intrusion developed as costal population
centers over-developed local ground water resources to meet
their water supply needs. The earliest published reports,
dating from mid-19th century in England, describe increasing
salinity of well waters in London and Liverpool. As the
number of localities experiencing intrusion has grown
steadily with time, so has recognition of the problem.
Today, sea water intrusion exists on all continents as well
as on many oceanic islands.
More than 70 years ago two European investigators found
that saline water occurred underground near the coast at a
depth of about 40 times the height of fresh water above sea
level. This distribution, known as the Ghyben-Herzberg
relation after its discovers, is related to the hydrostatic
equilibrium existing between the two fluids of different
densities. Although coastal intrusion is a hydrodynamic
rather than a hydrostatic situation, the relation is a good
first approximation to the sea water depth for nearly
horizontal flow conditions, where head differences in the
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two fluids exist, refinements in the relation (Luscynski and
Swarzenski, 1966) give improved results.
Intru8ign_in_the_United States
Almost all of the coastal states of the United States
have some coastal aquifers polluted by the intrusion of sea
water. Florida is the most seriously affected state,
followed by California, Texas, New York, and Hawaii.
The Florida problem stems from a combination of
permeable limestone aquifers, a lengthy coastline, and the
desire of people to live near the pleasant coastal beaches.
intrusion has been identified in 28 specific locations
(Black, 1953). Some 18 municipal water supplies have been
adversely affected since 192U. In the Miami area intrusion
has long been a problem and was seriously augmented by
interior drainage canals which lowered the water table and
permitted sea water to advance inland by tidal action.
In California, the large urban areas concentrated in
the coastal zone have caused sea water intrusion in 12
localities; seven others are threatened, and 15 others are
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regarded as potential sites (California Department of Water
Resources, 1958). Most of the affected areas contain
confined aquifers, and salinity increases can be traced to
the lateral movement of sea water induced by overpumping.
Major programs to control intrusion have been implemented in
Southern California. In Texas, intrusion is occurring in
the Galveston, Texas City, Houston, and Beaumont-Port Arthur
areas and around Corpus Christi. Saline water is moving up-
dip from the Gulf of Mexico in the confined Coastal Plain
sediments. The problem in New York is centered around the
periphery of the heavily pumped western half of Long Island.
The basalt aquifers of Honolulu, Hawaii have been
extensively intruded by sea water due to continued overdraft
conditions.
Environmental Consequences
Because of its high salt content, as little as two
percent of sea water mixed with fresh ground water can make
that portion of the aquifer unusable in terms of the U.S.
Public Health Service drinking water standard for total
dissolved solids. Thus, only a small amount of intrusion
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can seriously threaten the continued use of an aquifer as a
water supply source.
Once invaded by sea water, an aquifer may remain
polluted for decades. Even with application of various
control mechanisms, the normal movement of ground water
precludes any rapid displacement of the sea water by fresh
water. Prolonged abandonment or restricted use of the
underground resource may be required.
Causal Factors
The usual cause of sea water intrusion in coastal
aquifers is over-pumping. Pumping lowers the ground water
level. The effect is depression of the ground water table
in unconfined aquifers or alterations of the piezometric
surface in confined aquifers. Either event will reduce the
fresh water flow to the ocean. Thus, even with a seaward
gradient, sea water can advance inland. If pumping is
sufficiently great to reverse the gradient oceanward, fresh
water movement ceases and sea water may invade the entire
aquifer.
29
-------
In flat coastal areas, drainage channels or canals can
cause intrusion, in two ways. One is the reduction in water
table elevation and its associated decrease in underground
fresh water flow. The other is tidal action. If the
channels are open to the ocean, tidal action can carry sea
water long distances inland through the channels, where it
may infiltrate and form fingers of saline water adjoining
the channels.
In most oceanic islands fresh water forms a lens
overlying sea water. If a well within the fresh water body
is pumped at too high a rate, the underlying sea water will
rise and pollute the well. Wells can also serve as means of
vertical access; sea water in one aquifer may move into a
fresh water aquifer lying above or below the saline zone.
Pollutant Movement
The interface between underground fresh and saline
waters has a parabolic form. The salt water tends to
underride the less-dense fresh water. Under equilibrium
conditions, the sea water/fresh water interface is
essentially stationary, while the fresh water flows seaward.
30
-------
The length of the intruded wedge of sea water varies
inversely with the magnitude of the fresh water head. Thus,
a reduction of fresh water head is sufficient to cause
intrusion; reversed flow is not required.
Because sea water intrusion represents displacement of
miscible liquids in porous media, diffusion and hydrodynamic
dispersion tend to mix the two fluids. The idealized
interfacial surface becomes a transition zone. The
thickness of the zone is highly variable; steady flows
minimize the thickness, but nonsteady influences such as
pumping, recharge, and tides increase the thickness.
Measured thicknesses of transition zones range from a few
feet in undeveloped sandy aquifers to hundreds of feet in
overpumped basalt aquifers.
Flow within the transition zone varies from that of the
fresh water body at the upper surface to near-zero at the
lower surface. The movement in the transition zone
transports salt to the ocean. Continuity considerations
suggest that the salt discharge must come from the
underlying sea water dispersing upward into the zone. It
follows that there must be a landward sea water flow as
31
-------
sketched in Figure 1. This circulation has been verified by
a field investigation at Miami, Florida (Cooper, et al,
GROUND SURFACE
Figure 1. Schematic vertical cross section showing
fresh water and sea water circulations with a
transition zone.
Control Methods
A variety of methods have been proposed or utilized to
control sea water intrusion.
Control of Pumping Patterns If pumping from a coastal
ground water basin is reduced or relocated, ground
water levels can be caused to rise. With an increased
32
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seaward hydraulic gradient, a partial recovery from sea
water intrusion can be expected. Figure 2 illustrates
the effect of moving pumping wells inland in a coastal
confined aquifer.
PUMPING WELLSv ,
GROUND SURFACE
OCEAN
•SALT-WATER WEDGE
(a)
GROUND SURFACE
A- PUMPING WELLS
OCEAN
' SALT - WATER WEDGE
(b)
Figure 2. Control of sea water intrusion in a confined
aquifer by shifting pumping wells from (a)
to (b) an iniand
Artif icial.Recharge sea water intrusion can be controlled
by artificially recharging an intruded aquifer by the
use of surface spreading areas or recharge wells. By
33
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offsetting potential overdrafts, water levels and
gradients can be properly maintained. Spreading areas
are most suitable for recharging uncohfined aquifers,
and recharge wells for confined aquifers.
Fresh_Water_Rid2e Maintenance of a fresh water ridge in an
aquifer paralleling the coast can create a hydraulic
barrier which will prevent the intrusion of sea water.
A line of surface spreading areas would be appropriate
for an unconfined aquifer, whereas a line of recharge
wells would be necessary for a confined aquifer. A
schematic cross section of the flow conditions within a
confined aquifer is shown in Figure 3. With a line of
recharge wells paralleling the coast, the ridge would
consist of a series of peaks and saddles in the
piezometric surface. The required elevation of the
saddles above sea level will govern the well spacing
and recharge rates required. The ridge should be
located inland of a saline front so as to avoid
displacing the sea water farther inland. This control
method has the advantage of not restricting the usable
ground water storage capacity. The disadvantages are
-------
high installation and operational cost and the need for
supplemental water which may be lost to the sea.
RECHARGE WELL
I
GROUND SURFACE
PIEZOMETRIC SURFACE
OCEAN
NSALT WATER V- FRESH WATER
Figure 3 Control of sea water intrusion by a line
of recharge wells to create a pressure
ridge paralleling the coast (Todd.
1959) .
Injection wells have been extensively and successfully
employed along the Southern California coast. A new
project underway in Orange county, California, will
inject a combination of reclaimed wastewaters and
desalted sea water (Gofer, 1972). Details of well
construction are available in a report on the Los
Angeles West Coast Basin barrier (Mcllwain et al,
1970) .
35
-------
Extraction_Barrier Reversing the ridge method, a line of
wells may be constructed adjacent to and paralleling
the coast and pumped to form a trough in the ground
water level. Gradients can be created to limit sea
water intrusion to a stationary wedge inland of the
trough, such as illustrated in Figure 4 for a confined
aquifer. This method reduces the usable storage
capacity of the basin, is expensive, and wastes the
mixture of sea and fresh waters pumped from the trough,
The trough method has been successfully tested at one
location on the Southern California coast (California
Department of Water Resources, 1970).
PUMPING
WELL GROUND SURFACE
• plEZOMETRIC
SURFACE
OCEAN
'SALT NSTABLE^ FRESH WATER
WATER SALT-WATER
WEDGE
Figure U Control of sea water intrusion by a line
of pumping wells creating a trough
paralleling the coast (Todd, 1959).
36
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CQmbination_.Injection-Extraction Barrier using the last two
methods, a combination injection ridge and pumping
trough could be formed by two lines of wells along the
coast. Figure 5 shows a schematic cross section of the
method for a confined aquifer. Both extraction and
recharge rates would be somewhat reduced over those
required using either single method. The total number
of wells required, however, would be substantially
increased.
EXTRACTION FIELD
IN BASIN
I . 4 M
PEIZOMETRIC
SURFACE
Figure 5 control of sea water intrusion by a
combination injection-extraction barrier
using parallel lines of pumping and
recharge wells (after California
Department of Water Resources, 1966).
37
-------
subsurface Barrier By constructing an impermeable
subsurface barrier through an aquifer and parallel to
the coast, sea water would be prevented from entering
the ground water basin. Figure 6 shows a sketch of
such a barrier in a confined aquifer. A barrier could
be built using sheet piling, puddled clay, emulsified
asphalt, cement grout, bentonite, silica gel, calcium
acrylate, or plastics. Leakage due to the corrosive
action of sea water or to earthquakes would need to be
considered in a barrier design. The method would prove
most feasible in a narrow, shallow sinuous aquifer
connecting with a larger inland aquifer. Although
expensive, a barrier would permit full utilization of
an aquifer.
38
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EXTRACTION FIELD
IN BASIN
GROUND
SURFACE
SEA LEVEL
PIEZOMETRIC
SURFACE"!
Figure 6 Control of sea water intrusion by
construction of an impermeable
subsurface barrier (after California
Department of Water Resources, 1966).
Tide_Gate_control Wherever drainage channels carry surplus
waters from low-lying inland areas to the ocean, there
is a danger of sea water penetrating inland during
periods of high tides, if the channels are unlined, as
is often the case, the sea water may immediately invade
the adjoining shallow aquifers. To control such
intrusion, tide gates should be installed at the outlet
of each channel. These will permit drainage water to
be discharged to the ocean but prevent sea water from
advancing inland. This control method has operated
successfully for many years in the Miami, Florida,
area.
39
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Monitoring Procedures
i
Whatever the method of sea water intrusion control
adopted, a monitoring program will be a necessary part of
the system. Conditions both within and outside of the
intruded zone should be measured. Data will be required on
ground water levels and chloride concentration. The
vertical profile of the transition zone should be determined
at a few key locations.
In general, observation wells should be located so as
to provide a comprehensive picture of the local intrusion
situation: along any line of control, on the seaward side,
and on the landward side. The number of wells required can
vary with individual circumstances; however, the fact that
30 observation wells were drilled for each mile of recharge
line in the west coast Basin of Los Angeles (Mcllwain, et
al, 1970) is indicative that a reasonably dense network may
be required.
Observation wells should be measured for ground water
levels and chloride concentration (or total dissolved
solids) at intervals of one to two months under normal
-------
circumstances. Electrical conductivity logs should be run
in selected wells on a similar frequency.
Most observation wells for the Los Angeles injection
barrier were cased with 4-inch PVC plastic pipe in a gravel-
packed and grouted 14-inch diameter hole (Mcllwain, et al,
1970). For economic reasons multiple casings into as many
as three aquifers were placed in the same drill hole. This
required a 22-inch diameter drill hole with each of the
gravel-packed casings grouted between the aquifers to
prevent communiciation.
-------
References
1. Ballentine, R.K. , Reznek, S.R., Hall, C.W., Subsurface
Pollution Problems in the United States, U.s7
Environmental Protection Agency, Technical Studies
Report TS-00-72-02, 1972.
2. Black, A.P., et al. Salt Water Intrusion in Florida -
1953, Water Survey 6 Research Paper No. 9, Florida
State Board of Conservation, 38 pp (1953).
3. California Department of Water Resources, Sea-Water
Inclusion in California. Bulletin 63, 91 pp plus "~
appendices and supplements (1958).
1. California Department of Water Resources, Ground Water
!§§ln P£P±ection Projects; Santa Ana Gap. Salinity
Barrier, Orange County, Bulletin 147-1, 194 pp (1966).
5. California Department of Water Resources, Ground Water
2l§iD PE2t££ti2n Projects; Oxnard Basin Experimental
Extraction -Type Barrier, Bulletin 147-6, 157 pp
(1970) .
6. Cofer, J.R., "Orange County Water District's Factory
21," Journal Irrigation and Drainage Division, American
Society of Civil Engineers, Vol. 98, No. IR4, pp 553-
467 (1972).
7. Cooper, H.H., Jr., et al, Sea Water in Coastal
Aquifers. US Geological Survey Water-Supply Paper 1613-
C, 84 pp (1964).
8. Louisiana Water Resources Research Institute, Salt-
water Encroachment into Aquifers, Bulletin 3, Louisiana
State University, Baton Rouge, 192 pp (1968).
9. Luscynski, N,J., and Swarzenski, W.V., Salt-Water
Encroachment in Southern Nassau and Southeastern Queens
Counties. Long Island, New York, US Geological Survey
Water-supply Paper 1613-F, 76 pp (1966).
10. Mcllwain, R.R., et al. West Coast Basin Barrier Project
196_7^196_9, Los Angeles County Flood Control District,
Los Angeles, California, 30 pp plus appendices (1970).
42
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11. Parker, G.G., et alf Water Resources of Southeastern
Ei2£i
-------
UPSTREAM ENCROACHMENT OF SEA WATER
Estuaries of large rivers have since ancient times
offered convenient shelter for shipping and provided harbor
locations for commerce inland and overseas. Associated
structures and facilities remained of modest size until the
relatively recent advent of deep-draft vessels which have
necessitated extensive deepening of channels, and hence
interference with the natural equilibrium between tidal
currents and fresh water flow. The construction of canals
in communication with estuaries or the sea has also served
to conduct sea water inland. Other man-made changes in the
upstream environment; control of fresh water flow for
irrigation, water supply, hydro-power and flood control, and
increased consumptive withdrawal of both surface and ground
waters have served to decrease stream discharges alter the
natural time sequence of hydrological events and further
disrupt the natural equilibrium where the fresh water meets
the sea.
-------
This section briefly discusses the causal factors and
pollutant movement associated with upstream encroachment of
sea water and its environmental consequences. Thereafter,
control methods and monitoring procedures are presented
together with selected references to sources for more
detailed information.
Encroachment in_the United States
In the United States upstream migration of sea water is
concentrated primarily on the East and Gulf coasts but is
also known on the West Coast. Nearly all of the coastal
States between New Hampshire and Louisiana have had problems
of this type. Streams of low gradients which are
characteristic of the gently sloping coastal plain of this
area require only moderate reductions in flow for sea water
encroachment to take place. In recent years, during
extended dry periods sea water has migrated up the Delaware
River nearly as far as Philadelphia. Florida has had severe
sea water encroachment problems caused by construction of
drainage canals and channels; and harbor and channel
dredging has increased the salt water encroachment problem
U5
-------
in the Patapsco River in Maryland. These are but a few
representative examples of numerous incidences of sea water
encroachment along the East and Gulf Coasts.
Environmental conseguences
Upstream migration of the sea water wedge changes the
salinity of aquatic environments and may render fish and
wildlife habitats unsuitable for native populations. Sea
water encroachment can contaminate human and agricultural
water supplies necessitating costly treatment or relocation
of intake points. Increased salinity in the upstream
environment results in increased corrosion and shorter life
expectancy for engineering structures. Because of the high
salt content of sea water, exfiltration to the ground water
from the advancing sea water wedge can contaminate fresh
ground water supplies and leave them unsuitable for domestic
purposes long after the encroaching wedge has migrated back
down stream.
-------
Causal Factors and Pollutant Movement
Upstream migration of sea water is generally the result
of man's alteration of the hydraulic equilibrium that exists
between the fresh water and sea water regimes. The most
common causes of sea water encroachment in streams are
dredging of navigation channels, construction of sea level
canals, and reduction of stream flow.
Fresh water and sea water, being of different
densities, when brought together under stable conditions
tend not to coalesce but to form a distinct interface.
Normally, maximum tidal velocities are much larger in the
estuary portions of rivers than the mean velocities by which
fresh water flow reaches the sea. The tidal velocities
oscillate the salt water wedge back and forth with tidal
stage and in doing so generate turbulent shear flows that
cause mixing at the salt water/fresh water interface. If
the tidal shear flows are weak and unable to overcome the
stabilizing effects of the density difference between the
sea water and the fresh water, a stratified condition with a
very thin zone of mixing between the fresh water and the sea
water results, if the shear flow induced by tidal action is
-------
sufficiently strong to overcome the stabilizing effects
caused by the density difference between the two waters,
increased mixing results and sea water encroachment is no
longer characterized by a distinct interface but by a broad
zone of mixing.
The interaction of river flow and tidal currents
results in a net upstream bottom movement of sea water with
fresh water overriding this wedge in a seaward direction.
The position of the interface between the fresh water and
sea water is dependent on channel geometry, river discharge,
and high tide height. A change in any of these parameters
will cause the salt water/fresh water interface to migrate.
Reduction of stream flow or deepening of channels results in
landward migration of the sea water wedge while increased
stream flow results in a seaward migration.
Control Methods
Methods for control of sea water encroachment in
streams rely on maintaining adequate fresh water flow or
construction of physical barriers to prevent migration of
the sea water landward. Maintenance of fresh water flow
-------
generally can not be achieved by any single technique, but
requires basin wide management of withdrawal, recharge, and
storage of both surface and ground waters. Since most
surface streams receive part of their flow from the ground
water reservoir during all or part of the year, any
procedure that recharges the ground water system will also
aid in maintaining stream flow and in retarding sea water
encroachment. The primary elements of basin wide water
management that aid in controlling sea water encroachment in
streams include the following:
Ground Water Recharge The ground water reservoir can be
thought of as the regulator of base stream flow.
Much of the water that falls on the land
percolates to the ground water reservoir and is
slowly and steadily discharged to surface streams.
If the ground water reservoir is depleted through
overdraft or impediment of natural recharge (e.g.
paving of large areas and diversion of
precipitation to storm sewers) water is not
available in the subsurface to maintain sufficient
stream flow to prevent sea water encroachment
during dry periods. Much of the water that runs
-------
off during storms can be diverted to the
subsurface by construction of recharge basins.
This technique is particularly amenable to highway
storm drainage and is thoroughly discussed in a
report by Weaver (1971). The recharge of high
quality waste waters such as cooling waters or
tertiary treated sewage by the use of recharge
wells or surface spreading also aids in
maintaining the subsurface water supply. These
techniques are discussed in the section on sea
water intrusion into coastal aquifers.
Surface Water Impoundment and Regulated Release Stream flow
can be regulated and sea water encroachment
retarded by impounding excess surface waters
during periods of high runoff and releasing these
waters during periods of low stream flow. The
economics of such projects and the large volumes
of water required generally preclude their
undertaking solely for sea water intrusion
control. This contingency, however, should be
incorporated in plans for impoundment structures
for flood control, irrigation, and recreation.
50
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Tide Gates and Locks Where channels with low gradients meet
the sea there is always a danger of sea water
encroachment during periods of high tide and low
flow. The installation of tide gates for control
of such encroachment is discussed in the section
on sea water intrusion into coastal aquifers. Sea
water can also migrate upstream through navigation
locks in shipping canals when water is taken into
the locks from the seaward side and released on
the landward side. This type of sea water
encroachment can be reduced or eliminated by
controlled filling and emptying of the locks.
These techniques are discussed in reports by
Blanchet and Quetin (1972) and Bogges (1970).
Monitoring Procedures
A monitoring program should be an integral part of any
program for control of sea water encroachment. Monitoring
should be sufficient to determine the location and geometry
of the salt water/fresh water interface at any time and to
relate movement of the interface to the causal factors. In
general, monitoring points should be located on the landward
51
-------
side of locks and tide gates and near the mouths of tidal
channels to give a longitudinal profile of salt
concentrations in the upstream direction. The number of
monitoring points required will vary with local conditions
and extent of sea water encroachment. Monitoring points
should be measured for chloride levels (or total dissolved
solids) at monthly intervals during normal conditions and
more frequently when sea water is actively encroaching.
52
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References
1. Blanchet, Ch. and Quetin B. , "Mardyck Locks as Salt-
water Barrier", Journal of the Waterways, Harbors^ and
Coastal Engineering Division, ASCE, Vol. 98, No. WW4,
Proc. Paper 93877 Nov. 1972, pp. 561-567.
2. Boggess, Durward H. , A Test of Flushing Procedures to
Control Salt Water Intrusion at the W^ P., Franklin Dam
Near Ft.. Myers, Florida, Information Circular No. 62,
state of Florida Department of Natural Resources, 1970.
3. Weaver, Robert J., Recharge Basins for Disposal of
Si9il^§.Z Storm Drainage, Research Report 69-2,
Engineering Research and Development Bureau, New York
State Department of Transportation, May 1971.
4. Ippen, Arthur T. , "Salt- Water Fresh-Water Relationships
in Tidal Channels", Proc. Second Annual Am., Water Res.
PP ^7-55, Nov. 22,~~1966.
5. Owen, Langdon W. , "Salinity Intrusion and Related
Studies Sacramento - San Joaquin Delta", International
Commission on Irrigation and Drainagej. * Vol. H pp.
2lTl5 -~21.35,~1966.
53
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SALINE WATER IN INLAND AQUIFERS
the Problem
Hydrologic data accumulated in recent years indicate
that large quantities of saline water exist under diverse
geologic and hydrologic environments in the United States.
Most of the nation's largest inland sources of fresh ground
water are in close proximity to natural bodies of saline
ground water.
Saline water is an inherent constituent of marine-
derived sedimentary rocks which form some significant
aquifers exploited today. Waters with high natural mineral
content can be found at relatively shallow depths throughout
large portions of the United States. Fresh water recharge
has flushed much of the saline water from many aquifers
throughout geologic time, saline water may remain at depth
or where exposure to fresh water recharge has not occurred.
Brines occur in almost all areas at the depths explored and
developed by the oil industry.
-------
According to the Task Committee on Salt Water
Intrusion, 1969, saline water in inland aquifers may be
derived from one or more of the following sources:
Sea water which entered aquifers during deposition
or during a high stand of the sea in past geologic
time
Salt in salt domes, thin beds, or disseminated in
the geologic formations,
Slightly saline water concentrated by evaporation
in playas or other enclosed areas,
Return flows from irrigated lands,
Man's saline wastes.
When development of an aquifer by acts of man causes
saline water from any of these sources to move into the
fresh water aquifer, salt water intrusion results.
55
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Intrusion in the United states
Considerable information exists on the geographic
distribution of saline ground water (here defined as water
containing more that 1,000 mg/1 dissolved solids)(Feth,
1965; Feth, et al, 1965; Task Committee on Salt Water
Intrusion, 1969). These reports indicate that approximately
two-thirds of the conterminous United States is underlain in
part by saline ground water.
In the Atlantic and Gulf Coastal Plain and in many
ground water basins on the Pacific coast, saline water
occurs because of sea water that was trapped in the
sediments during deposition (connate water) or that invaded
the sediments during previous high stands of the sea.
In the Midwest, bedrock aquifers generally contain
mineralized water at depths below about 122 meters.
Aquifers with saline waters of more than 1,000 mg/1
dissolved solids underlie fresh-water aquifers throughout
most of the Great Plains area from central Texas to Canada.
In the mountainous area from the Rocky Mountains to the
56
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Pacific Coast, saline water occurs at depth in many ground
water basins.
Environmental Consequences
intruded fresh-water aquifers typically are locally
affected. Because of the relatively slow movement of ground
water, saline water intrusion may produce detrimental
effects on ground water quality that could persist for
months under the most favorable circumstances, or many years
or decades in other cases.
Causal Factorg
Salt water intrusion can result from several
mechanisms. One involves the upward movement of saline
water through the aquifer as a result of some act of man on
the hydrologic regime, such as overpumping. Another occurs
by saline water moving vertically through wells into a
fresh-water aquifer. Saline water intrusion also can occur
where construction of a waterway or channel involves removal
of materials which have acted as an impermeable blanket
between saline waters and fresh-water aquifers. Destruction
57
-------
of natural barriers may also permit saline water on the
surface to be carried past natural geologic barriers, such
as faults which previously protected the fresh-water
aquifer.
Pumping of an aquifer underlain by saline water will
cause the ground water level to be lowered, which in turn
can cause an upconing of the saline water into the aquifer
and eventually the well itself. Figure 7 shows the sequence
of upconing to a pumping well in an unconfined aquifer.
Where saline and fresh-water aquifers are connected
hydraulically, dewatering operations, as for quarries,
roads, or excavations, may cause vertical migration of
saline water. Similarly, the deepening or dredging of a
gaining stream will cause a lowering of the head in the
aquifer near the stream. If the aquifer is hydraulically
connected to an underlying saline aquifer, the lowering of
head will induce upward movement of saline water. Figure 8
illustrates the zone of saline water intrusion produced when
a water table is lowered. This indicates that encroachment
of saline water can be a potential problem where flood
control or other projects modify stream stages.
58
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Extensive pollution of fresh water aquifers has been
caused by vertical leakage of saline water through inactive
or abandoned wells or test holes. A well is an avenue of
nearly infinite vertical permeability through which saline
water may move. Pumping from fresh-water aquifers may lower
water tables below the piezometric surfaces of lower saline
water zones. Examples of saline water moving upward into a
fresh-water aquifer through various types of wells are
sketched in Figure 9.
59
-------
fffffff/f f f f f f f f
FRESH WATER
SALINE WATER
GROUND SURFACE
f f f r r f f r
INITIAL WATER TABLE
I WATER TABLE
<•• «•* ••*
INTERFACE REACHING
THE WELL
INITIAL INTERFACE
Figure 7 Schematic diagram of upconing of
underlying saline water to a pumping
well.
60
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:::;:::::::::::W:W:W:: LOWERED WATER TAB^E
ZONE OF SALINE WATER INTRUSION
ORIGINAL FRESH - SALINE WATER INTERFACE
Figure 8 Diagram showing upward migration of
saline water caused by lowering of water
1963) in a gaining strea>* (Deutsch,
61
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FRESH
WATER WELL
CORRODED
CASING
ABANDONED
OPEN HOLE
SALINE - WATER AQUIFER
Figure 9 Diagram showing interformational leakage
by vertical movement of water through
wells where the piezometric surface lies
above the water table (after Deutsch.
1963) .
Indicative of all of the above mechanisms is the
intrusion situation in Southern Alameda County, California,
shown in Figure 10. Here a combination of four causal
factors - natural and man-made - has lead to intrusion in
two distinct aquifers. Although the intruding water shown
here is sea water, the mechanisms apply equally to any
saline water source.
62
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SAN'FRANCISCO BAY
* SHALLOW GROUND WATER
•""•^^~ * Jt
. *. °. •' ,° . *
'O. . . • , . DEEPER GROUND WATER % 0
• O. O . o ** • 0 • . ' • • O • • 0 .
. O
0 • .o
e . '
00
CLAY
LEGEND
SAND AND GRAVEL
Y//A
SALT WATER
NOTE
1. Dl RECT MOVEMENT OF BAY WATERS THROUGH NATURAL "WINDOWS".
2. SPILLING OF DEGRADED GROUND WATERS.
3. SLOW PERCOLATION OF SALT WATER THROUGH RESERVOIR ROOF.
4. SPILLING OR CASCADING OF SALINE WATERS OR
DEGRADED GROUND WATER THROUGH WELLS.
Figure 10 Illustrative sketch showing four
mechanisms producing saline water
intrusion in Southern Alameda County,
California (after California Department
of Water Resources, 1960).
63
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Pol^utarit Movement
When an aquifer contains an underlying layer of saline
water and is pumped by a well penetrating only the upper
fresh water portion, a local rise of the interface below the
well occurs. With continued pur.pir.cj this upccning rises to
successively higher levels until eventually it may reach the
well. When pumpinq is stopped, the denser saline water
tends to subside to its original position.
The factors governing upconing include the pumping rate
of the well, the distance between the well and the saline
water, the duration of pumping, the permeability of the
aquifer, and the density difference between the fresh and
saline waters.
Upconing is a complex phenomenon. Quantitative
criteria have been formulated for the design and operation
of wells for skimming fresh water from above saline water
(Schmorak and Mercado, 1969). From a water-supply
standpoint it is important to determine the optimum
location, depth, spacing, pumping rate, and pumping sequence
to maximize production of fresh ground water while
minimizing the undermixing of fresh and saline waters.
-------
The movement: of saline water within wells is in the
direction of the hydraulic gradient. The flow can occur
either upward or downward, depending upcn the direction of
the head differential. Also, head differences may result
from natural geologic causes or from effects of pumping.
Typically, a well pumping from a fresh-water zone reduces
the head there to a value lower than that of other zones.
If the non-pumped zones contain saline water and are
connected hydraulically to the well, intrusion into the
fresh-water zone will result.
Control Methods
A variety of methods are available to control saline
water intrusion in aquifers. The selection of a particular
method will depend on the local circumstances responsible
for the intrusion. Alternative control methods are briefly
described in the following subsections.
Reduced Pumping Where pumping of a fresh-water aquifer
produces upconing of saline water, an effective control
method is to reduce pumping. This nay take the form of
actual termination of pumping, of reduction in the
pumping rate from individual wells, or of the
65
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decentralization of wells. The more pumpage is
reduced, the greater the tendency for the saline water
interface to subside and to form a horizontal surface.
Illustrative of the consequences of pumping rate are
data shown in Figure 11 from the Honolulu aquifer.
Here underlying saline water (actually sea water) in a
nearby observation well moves upward and downward in
accordance with the pumping rate of a well.
Increased Ground Water Levels In situations where
surface construction or excavations have lowered ground
water levels and caused underlying saline ground water
to rise (see Figure 8), any action which raises the
ground water level will be effective in suppressing
intrusion. Artificial recharge of an unconfined
aquifer, for example, would have a beneficial effect.
Similarly, raising surface water levels, as by
regulating stream stages or by releasing water into
surface excavations, will cause a corresponding upward
adjustment in the adjacent water table.
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Protective Pumping Because saline water moves into a
fresh water aquifer under the influence of a pressure
gradient, an effective control method is to reduce the
pressure in the saline water zone. This can be
accomplished by drilling and pumping a well perforated
only in the saline water portion of the aquifer.
Although the water pumped is saline and may present a
disposal problem, this method does permit the continued
utilization of the underground fresh water resources
without increasing intrusion. The method was
successfully applied to counteract a growing intrusion
problem in Brunswick, Georgia (Gregg, 1971).
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X
0
0
I-
440 —
400 —
a
a
uf
D
K
3
I 360
320
1964 1965
1966 1967
YEARS
1968
1969
Figure 11 Monthly variations of total draft and
chloride content in a nearby observation
well, Honolulu aquifer (after Todd and
Meyer, 1971).
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TO minimize the vertical movement of saline
water in abandoned wells and test holes, they should be
completely sealed by backfilling with an impermeable
material. Dumping of loose soil into a well seldom
provides an effective guarantee of impermeability,
particularly in a deep well. One method is to pump a
cement slurry into the well, filling from the bottom
upward. The material will then create a void-free
column having a lower permeability than that of the
surrounding formations.
Well Construction To control the movement of saline water
within active wells that are either pumping or resting
requires careful well construction. During the
Billing of a well, one or more zones of saline water
may be encountered, when the full depth of the well
has been reached, those formations expected to be
developed for fresh water production are selected.
Perforations should be placed only opposite the fresh-
water zones. Unperf orated casing should be placed
opposite saline water strata, with the annulus outside
of the casing carefully sealed to isolate saline zones
from the fresh-water zone. Details of well
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construction are available in standard references
(Campbell and Lehr, 1973; Gibson and Singer, 1971;
Toddr 1959).
Monitoring Procedures
When fresh-water aquifers need to be protected against
vertical intrusion, a monitoring network to verify the
effectiveness of the control method should be installed. In
general, the network will consist of observation wells
perforated within the fresh-water zone and sampled regularly
for total dissolved solids or electrical conductivity. The
monitoring wells should be in the deepest portions of the
fresh-water zone so as to reveal the first evidence of
intrusion, and spaced close enough to pumping wells that
upconing will be detected. Periodic checks should also be
made to ascertain that any newly abondoned wells or test
holes are properly sealed and long abandoned wells that are
identified through records search or other means should be
located and plugged. Regular measurements of pumping rates
and ground water level fluctuations, both natural and
artifically produced, will help to recognize causal factors
responsible for actual or incipient intrusion problems.
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References
1. Ballentine, R.K.r Reznek, S.R.r Hall, C.W. , Subsurface
Pollution Problems in the United states, U.S. "~
Environmental Protection Agency~Technical studies
Report TS-00-72-02, 1972.
2. California Department of Water Resources, Intrusion of
§§lt Water into Ground Water Basins of Southern Alameda
County., Bulletin 81, 44 pp (1960) .
3. Campbell, M.D., and Lehr, J.H., Water Well Technology.
McGraw-Hill, New York, 681 pp (1973).
4. De^tsch, M., Ground Water Contamination and Legal
Controls in Michigan, US Geological~Survey Water-Supply
Paper 1691, 79 pp (1963).
5. Feth, J.H., Selected References on Saline Ground Water
Resources of the United States, US Geological Survey
Circular 499, 30 pp (1965).
6. Feth, J.H., et al. Preliminary Map of the Conterminous
United States Showing DejDth £o and Quality of
Shallowest Ground Water Containing More than 1000 Parts
P§£ Million Dissolved Solids, us Geological Survey
Hydrologic Invests. Atlas HA-199 (1965).
7. Gibson, U.P., and Singer, R.D., Water Well Manual,
Premier Press, Berkeley, California, 156 pp (1971).
8. Gregg, D.O., "Protective Pumping to Reduce Aguifer
Pollution, Glynn County, Georgia", Ground Water. Vol.
9, NO. 5, pp 21-29 (1971).
9. Schmorak, S., and Mercado, A., "Upconing of Fresh
Water-Sea Water Interface Below Pumping wells. Field
Study", Water Resources Research. Vol. 5, No. 6, pp
1290-1311 (1969) . ~
10. Task Committee on Salt Water Intrusion, "Salt Water
Intrusion in the United States", Journal of Hydraulics
Division. American Society of Civil Engineers, Vol. 95.
No. HY5, pp 1651-1669 (1969).
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11. Todd, O.K., Ground Water Hydrology, John Wiley & Sons,
New York, pp 115-148 (1959) .
12. Todd, O.K., and Meyer, C.F., "Hydrology and Geology of
the Honolulu Aquifer", Journal of Hydraulics Division,
American Society of Civil Engineers, Vol. 97, No. HY2,
pp 233-256 (1971).
13. U.S. Environmental Protection Agency, subsurface Water
EP.lin£iP.!l ~ h Selective Annotated Bibliography - Part
II - Saline Water Intrusion, 1972.
IH. Winslow, A.G., and Doyel, W.W., Salt Water and Its
Relation to Fresh Ground Water in Harris county, Texas,
Texas Board of Water Engineers, Bulletin 5409, 37 pp
(1954) .
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INSTITUTIONAL AND LEGAL ASPECTS
Water Pollution Control Act As Amended
The Federal Water Pollution Control Act as 'Amended
recognizes, as a policy of the Congress, the primary
responsibility of the States to prevent, reduce, and
eliminate water pollution. The Adminisitrator of EPA is
directed to develop comprehensive programs for water
pollution control in cooperation with state and local
agencies and with other Federal agencies. Thus, the laws
and institutions relating to water, and their adequacy, are
of basic importance. In most states, the functions of
administration of water rights and of water pollution
control are the responsibility of different state agencies.
Water Rights
Any attempt to control an activity involving the
diversion and use of surface or ground waters, in order to
prevent water pollution, will probably involve vested water
rights and usually will be in conflict with these water
rights. For many streams, ground water basins, and aquifers
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throughout the United States, rights to the full yield have
long since been vested, either through actual diversion and
use, or because of the riparian status of lands or ownership
of overlying lands, even though no use of water is being or
has been made.
There is little question that the Federal Government
has the constitutional power to control the use of most of
the surface waters of the United states. Under the
reservation doctrine, confirmed by the United States Supreme
Court in Arizona vs California, 373 US 546 (1963), the
Federal Government can control and use the waters
originating on or flowing across reserved or withdrawn
public lands. A large proportion of the natural runoff of
the western states originates on such lands, under the
jurisdiction of the US Forest Service, the National Park
Service, and other Federal agencies. The federal power to
control navigable waters has long been established and
confirmed by a series of US Supreme Court decisions. The
Court definitions of what constitutes navigable waters are
broad enough to encompass nearly all surface streams of any
significant magnitude and their tributaries (United States
vs Grand River Dam Authority, 363 US 229, 1960).
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The Federal Government has never elected to assert
these constitutional powers over stir face waters in a general
manner except with respect to control of pollution resulting
from disposal of wastes. Rather, the Congress has
repeatedly stated that the states shall control the use of
intrastate waters. Section 8 of the Reclamation Act of 1902
(32 Stat. 388, 1902) explicitly provides that the Secretary
of the Interior shall obtain water rights for reclamation
projects in accordance with state water laws. The same
provision or one expressing the same intent has been
included in acts amendatory of and supplementary to the
original Reclamation Act, and in numerous other enactments
concerning water resources, including the Flood Control Act
of 19au (58 Stat. 887, 1944).
In further support of this apparently consistent
congressional intent, it is significant that there are no
federal statutes governing the allocation of water
resources, surface or ground, or the administration of water
rights. Although periodically bills are introduced in
Congress for those purposes, they have never passed beyond
the committee stage. Up to 1973, therefore, responsibility
for the allocation of water resources and the granting and
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administration of rights to intrastate waters has been left
to the states. Interstate compacts have been executed for
many of the more significant interstate streams systems.
Some of these (the Delaware River Basin compact, for
example) encompass the associated interstate aquifers. To
date, federal power over ground water resources has been
asserted only in specific instances involving water supplies
for federal installations (State of Nevada vs United States,
165 F. Supp. 600, 1958). Indian water rights, now almost
entirely unquantified, and apparently definable only by
individual actions brought before the US Supreme Court, are
becoming highly controversial and becloud the entire water
rights situation over much of the United States. For
surface waters, the riparian doctrine of water rights is
followed in several of the eastern, southern, and midwestern
states; only Florida, Indiana, Iowa, Minnesota, Mississippi,
New Jersey, and Wisconsin have strong statutes governing the
diversion and use of such waters. In other states, the
appropriation doctrine is followed, and the right to divert
and use surface water must be acquired in accordance with
state law. Most of these state laws are based on the
objective of maximizing the economic beneficial uses for
municipal and industrial water supply, irrigation, power
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production, and the like. With but few exceptions (eg,
California) state water rights laws do not provide
adequately for water quality control and in-stream uses
such as for fish and wildlife resources. Generally, the
hydrologic and hydraulic interrelationships of surface
waters and ground waters are not recognized in state water
laws.
Some states (Colorado, Florida, Indiana, Iowa,
Minnesota, Nevada, New Jersey, New Mexico, and Utah) have
statutes governing the extraction and use of ground water.
The State Water Resources control Board of California has
only the power to initiate an adjudicatory action in the
courts; imposition of a physical solution depends upon a
finding that such action is necessary to prevent destruction
of or irreparable damage to the quality of ground waters
(Sec. 2100 et seq, Water Code). Most ground water laws have
been laid down by the courts and vary widely from state to
state. In California, for example, the courts follow the
correlative doctrine, whereas in Texas, the courts have
consistently followed the doctrine of absolute ownership or
the rule of capture (City of Corpus Christi vs city of
Pleasanton, et al, 154 Tex. 289, 276 S.W. 2» 798, 1955).
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Under the later doctrine, it is impossible to control the
extraction and use of ground water in any significant way,
although certain limited powers to control well spacing,
thus affecting extraction rates, are granted to underground
water conservation districts formed in a few areas of the
state (Chap. 52, Texas Water Code).
Present state statutes and case law concerning the
rights to the use of water are completely inadequate to
control the pollution of ground water that might result from
the diversion and use of either surface or ground water.
State laws need to be revised and broadened, as has been
recommended by the National Water Commission (1972).
Ground Water Basin Management
Concept
The concept of managing a ground water basin is
analogous to the operation of a surface water reservoir. By
regulating the releases of water from a dam, the reservoir
can be made to serve various beneficial purposes, and with
planning the benefits can be optimized. In general, the
benefits depend not on maintaining the reservoir full or
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empty at all time but rather on varying the water level to
meet predetermined supply and demand criteria.
Ground water basins are increasingly being recognized
as important resources for water storage and distribution.
Ground water reservoirs have numerous advantages over
surface reservoirs: Initial costs for storage are
essentially zero, siltation is not a problem, eutrophication
is not a problem, water temperatures and mineral quality are
relatively uniform, evaporation losses are negligible,
turbidity is generally insignificant, no land surface area
is required, and useful lives are often idefinite.
The objective of ground water basin management is
generally to provide an optimal continuing supply of ground
water of satisfactory quality at minimum cost. To reach
this objective requires comprehensive geologic and
hydrologic investigations , development of a model to
simulate the aquifers, economic analyses of alternative
operational schemes, and finally, based on this management
study, regulation of the basin. In most cases conjunctive
use of surface water and ground water systems is considered
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in seeking a maximum water supply at minimum cost (Todd,
1959) .
Procedure
The management study leading to a basin operation
consists of the components listed below. These are arranged
to indicate the usual sequential order employed.
Geologic Phase
Data collection and water level maps
Storage capacity and change; transmission
characteristics
Water quality analysis
Hydrologic Phase
Data collection
Base period determination
Water demand
Water supply and consumptive use
Hydrologic balance
Mathematical Model
Programming and parameter development
Validation
Operation-Economic Phase
Future water demand and deep-percolation
criteria
Analysis of cost of facilities
Cost-of-water study
Plans of operation
Cost comparision of plans
Preparation of Report
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Physically, the management of a basin involves
regulating the patterns and schedules of recharge and
extractions of water. This would include specifying the
number and location of wells together with their pumping
rates and annual limitations on total extractions. The
upper and lower ground water levels would be defined. Water
quality objectives would be set, and sources and causes of
pollution carefully controlled. The artificial recharge of
storm flows, imported water, or reclaimed water could be
involved. In some instances, measures to limit sea water
intrusion and land subsidence would be included.
Because of the dynamic nature of ground water resource
systems, a continuing data collection program is essential.
Management parameters and criteria must be re-evaluated at
intervals of five to ten years.
Detailed management studies for several basins in
California have been undertaken (Calif. Dept. of Water
Resources, 1968).
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Sources^of Basin Pollution
Within a ground water basin the potential sources of
pollution may include all of the possibilities previously
described as well as many others. A pollution source unique
to basin management may be artificial recharge of ground
water. In order to increase the available ground water
supply, a basin may be heavily pumped so as to lower ground
water levels. Thereafter, water can be artificially and
naturally recharged to fill the available underground
storage space. Recharging is usually accomplished by
surface spreading in which water is released for
infiltration into the ground from basins, ditches,
streambeds, or irrigated lands (Muckel, 1959). Water can
also be recharged into confined aquifers through injection
wells. If the quality of the recharged water is inferior to
that of the existing ground water, pollution will result.
An excellent illustration is the situation in Orange
County, California (Moreland and Singer, 1969). To
compensate for extensive overdraft of the ground water basin
during the 1940*s, large quantities of imported Colorado
River water were subsequently recharged underground along
the Santa Ana River channel. Because of the high salt
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content of the imported water, the salintiy of a substantial
portion of Orange County's ground water has been
significantly increased.
On a long-range basis, maintenance of salt balance in a
basin, i.e., prevention of accumulation of salts, must be
achieved. This is the most difficult quality-maintenance
problem.
Control^Methods
Proper management of a ground water basin requires an
appropriate institutional structure embracing the basin to
insure that the water quality is not adversely affected.
Control methods could include the following:
Maintaining ground water levels below some shallow
depth so as to minimize the opportunity for pollution
from surface sources.
Maintaining ground water levels above some greater
depth in order to avoid upward movement of more saline
and warmer water into the aquifer.
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Regulating the quality of water artificially recharged
to the aquifers. Storm runoff collected in upstream
reservoirs and then released into spreading areas is
usually of higher quality than ground water, but
imported and reclaimed water may not be.
Preventing sea water intrusion and the inflow of poor-
quality natural waters from adjacent surface and
subsurface sources. Poor-quality water from
underground sources can usually be excluded by lines of
pumping or recharge wells, while surface waters can be
intercepted by drainage ditches and diverted from the
basin.
Regulating the drilling, completion, and operation of
all types of wells.
Regulating land use over the basin to prevent the
development of sources of ground water pollution.
Reducing salt loads by exporting saline ground waters,
wastewaters, or brines from desalted water supplies.
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Monitoring the quality of ground water throughout the
basin to identify and to locate any pollution sources
and to verify corrective measures.
Legal_and_I institutional Requirements
Ground water management is not explicitly mentioned in
the Federal Water Pollution Control Act as Amended, but is
essential if the maximum overall benefit is to be derived
from development and use of the underground resources, while
at the same time protecting and maintaining ground water
quality. The many interrelated sources and causes of ground
water pollution and the inherent complexity of ground water
resource systems make it mandatory that the problem of
pollution control be approached on a "systems" basis through
management, if control is to be effective.
Ground water management may be defined as the
development and utilization of the underground resources
(water, storage capacity and transmission capacity) ,
frequently in conjunction with surface resources, in a
rational and hopefully optimal manner to achieve defined and
accepted water resource development objectives. Quality as
well as quantity must be considered. The surface water
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resources involved may include imported and reclaimed water
as well as tributary streams.
Generally, management can be most effectively
accomplished at the local or regional governmental level,
operating within a framework of powers and duties
established by state statutes. A few such local management
agencies with adequate powers have been formed and are
operating; an example is the Orange County Water District,
California (Orange County Water District Act, as amended).
Except for California, there are few, if any, state
statutes under which effective management agencies can be
established and operated. Current statutes and case law
concerning water rights impede, and in some cases block,
effective management. Principal weaknesses in the present
legal and institutional posture at the state level with
regard to control of ground water pollution from sources and
causes other than waste disposal stem from these basic
points:
In most states, private ownership of ground water
attaches through ownership of the land surface, and the
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states have not enunciated or implemented jurisdiction
in terms of allocation or administration of the
resource.
State law and court decisions have generally dealt with
surface and ground water as separable resources.
Most state statutes and court decisions do not
recognize that pollution of both ground and surface
water may result from the effects of activities not
necessarily involving waste generation and disposal;
pollution has been narrowly defined.
When these three weaknesses are considered in their
total ramifications, it is evident that ground water
pollution control is possible only within the context of a
comprehensive management program for optimal allocation,
conservation, protection, and use of the water together with
related land resources available within a region.
The legal and institutional factors that must be
considered in a ground water pollution control program are,
as a consequence, largely dictated by the requirements of a
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management structure. Effective management of ground and
surface waters as interrelated and interdependent resources
is undertaken as a means of achieving regional, social,
environmental, and economic goals. Implementation of such
management requires that these goals be articulated; that
management tools required to allocate the total water
resource equitably among purposes, to abate and prevent
pollution, and to equitably allocate the cost involved, be
identified; and that government actions required for
management be initiated and carried forward.
The objectives sought by managing ground and surface
water resources on a conjunctive "systems" basis are not the
same from area to area, objectives that might be important
in one area, such as extending the life of the ground water
aquifer, protecting spring flows, or controlling subsidence,
might have little relevance elsewhere. Many alternative
institutional structures could be considered for the
management vehicle. But the extremely diverse hydrologic,
geologic, economic, legal, political, and social conditions
affecting the occurrence, protection, and use of ground and
surface waters in the United states suggest that no single
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structure would be universally applicable nor politically
acceptable.
While management entities might not have the same
organizational structure everywhere, certain geographic
characteristics, fundamental resource information, and
certain basic management powers and duties are commonly
required. Delineation of the geographic area to be
encompassed by a workable management entity must include
consideration of areas having definable hydrologic
boundaries. Furthermore, to the extent possible, the area
should have social and economic identity or common interests
and be generally contiguous with existing political
subdivi sion s.
Data and analysis are needed regarding a range of
hydrologic, geologic, physical, environmental, social, and
economic factors that will largely determine the processes
through which management objectives are attained. Through
development of new analytical techniques by which the
performance of a ground water basin under various conditions
can be simulated or modelled mathematically, computerized
management tools have become available. Depending upon
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their intended use, these models require adequate data (in
appropriate formats and on a timely basis) such as the
following:
Stream flow - normal and flood; water quality; waste
discharges - quantity and quality; silt loads;
precipitation; evaporation; storm and drought
frequency, duration, and intensity; water supply
facilities and costs; waste treatment processes and
costs.
Water uses; water rights; projected uses; return flow
— quantity and quality; projected economic,
demographic, and social trends; relationship between
the factors affecting water quality such as source of
pollutants, water development, water quality criteria
and objectives.
Available energy sources, facilities, and costs;
wildlife and fishery resources; recreational facilities
and uses; historic, esthetic, and scenic areas; unique
aquatic, zoologic, or biologic habitats.
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Areas, sources, rate and quality cf ground water
recharge; surface and ground water inflow-outflow
relationships; volume of aquifer storage capacity;
aquifer transmissibility, specific capacity, and
boundaries; volume of surface water storage; seasonal
relationships of water demand and water in storage;
relationships of surface and ground water use and
quantity and quality of return flows.
Social Problems and Goals
Assuming that adequate programs are conducted to gather
and make information available to a viable management
entity, that entity must be vested with powers and authority
to fully exercise a complex management function. Among
these powers and duties must be the following as recommended
by the National Water Commission (1972).
"State laws should recognize and take account of the
substantial interrelation of surface water and ground
waters. Rights in both sources of supply should be
integrated, and uses should be administered and managed
conjunctively. There should not be separate
codifications of surface water law and ground water
law; the law of waters should be a single, integrated
body of jurisprudence.
Where surface and ground water supplies are
interrelated and where it is hydrologically indicated,
maximum use of the combined resource should be
accomplished by laws and regulations authorizing or
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requiring users to substitute one source of supply for
the other.
The Commission recommends that states in which ground
water is an important source of supply immediately
commence conjunctive management of surface water
(including imported water) and ground water, whether or
not interrelated, through public management agencies.
The states should immediately adopt legislation
authorizing the establishment of water management
agencies with powers to manage surface water and ground
water supplies conjunctively; to issue bonds and
collect pump taxes and diversion charges; to buy and
sell water and water rights and real property necessary
for recharge programs; to store water in aquifers,
create salt water barriers and reclaim or treat water;
to extract water; to sue in its own name and as
representative of its members for the protection of the
aquifer from damage, and to be sued for damages caused
by its operations, such as surface subsidence.
The states should adopt laws and regulations to protect
ground water aquifers from injury and should authorize
enforcement both by individual property owners who are
damaged and by public officials and managment districts
charged with responsibility of managing aquifers."
Implementation of the National Water Commission's
recommendations would go far toward equipping a management
entity to control ground water pollution. There are many
other questions, however, largely unanswered in present
statutes and court decisions, that will require very careful
analysis.
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References
1. Amer. Soc. of Civil Engineers, Ground Water Management.
Manual on Engineering Practices No. 40, 216 pp (1972) .
2. Banks, H. 0., Federal-state Relation in the Field of
Western Water Rights and Important Auxiliary Questions,
Report prepared for the US Department of Agriculture.
August (1967).
3. California Dept. of Water Resources, Planned
Utilization of Ground Water Basins: coastal Plain of
Los Angeles County, Sacramento, 25 pp. (1968)."
4. Corker, C. E. , Ground Water Law^. Management and
Mroinistration, National Water Commission, Report No.
NWC-L-72-026 NTIS Accession No. PB 205 527, 509 pp
(1971) .
5. Davis, C., Riparian Water Law, A Functional Analysis.
National Water Commission, Report NWC-L-71-020, NTIS
Accession No. PB 205 004, 81 pp (1971).
6. Heath, M. S., Jr., A Comparative study of State Water
Pollution. Control Laws and Programs. Water Resources
Research Inst. Univ. of North Carolina, Rept. No. 42,
265 pp (1972).
7. Hines, N. W. , Public Regulation of Water Quality in the
United States, National Water Commission, Report NWC-L-
72-036, NTIS Accession No. P 308 209, 632 pp (1972).
8. Mack, E., Ground Water Management, National Water
Commission, Rept. NWC-EES-71-004, NTIS Accession No. PB
201 536, 179 pp (1971) .
9. Meyers, C. J., Functional Analysis of Appropriation
Law, National Water Commission, Rept. NWC-L-00?, NTIS
Accession No. PB 202 611, 72 pp (1971).
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10. Moreland, J.A., and Singer, J.A., Evaluation of Wa-ter-
QualitY Monitor ing. in the Orange County Water District,
California, USGS Open-Pile Kept., Menlo Park, Calif.,
27 pp (1969)
11. Muck el, D.C., Rejglenishment of Ground Water Supplies by.
Artificial Means, Tech. Bull. No. 1195, Agric. Research
Service, U.S. Dept. of Agriculture, 51 pp. (1959).
12. National Water Commission, Review Draft of Proposed
Report, 2 vols., 1127 pp (1972).
13. Orlob, G.T., and Dendy, B.B., "Systems Approach to
Water Quality Management," Jour.. Hydraulics Div^, Amer.
Soc. of Civil Engineers, vol. 99, no. HY U. pp 573-587
(1973) .
14. Santa Ana Watershed Planning Agency, California, Final
Report to Environmental Protection Agency (1973) . ~"
15. Todd, D.K. , Ground Water Hydrology, John Wiley & Sons,
New York, pp. 200-218 (1159).
16. Trelease, F.J., Federal- State Relations in Water Law,
National Water Commission, Kept. NWC-L-71-om , NTTS
Accession No. PB 203 600, 357 pp. (1971).
9U
•US. GOVERNMENT PRINTING OFFICE: 1973 546-311/13
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