GE-CLAS^
GROUNDWATER
POLLUTION CONTROL:
AN INTERIM REPORT
GE73TMP-19
GENERAL ELECTRIC COMPANY-TEMPO
CENTER FOR ADVANCED STUDIES
SANTA BARBARA, CALIFORNIA
CLASS 3
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CLASS 3
LIMITED AVAILABILITY INFORMATION
THE DRAFT MATERIAL USED TO PREPARE THIS REPORT
HAS UNDERGONE PRELIMINARY REVIEW BY THE ENVIRON-
MENTAL PROTECTION AGENCY SUT THE REPORT IN ITS
PRESENT FORM HAS NOT BEEN REVIEWED OR APPROVED BY
EPA AND IS, THEREFORE, CONSIDERED TO BE A DRAFT.
ORIGINAL DISTRIBUTION TO THOSE INDIVIDUALS WITH SPE-
CIFIC NEED. NOT TO BE REPRODUCED OR OTHERWISE DIS-
TRIBUTED EXCEPT WITH APPROVAL OF EPA OR TEMPO.
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GROUNDWATER POLLUTION CONTROL:
AN INTERIM REPORT
GE73TMP-19
May 25, 1973
Edited by
Charles F. Meyer
TEMPO
General Electric Company
Center for Advanced Studies
Santa Barbara, California 93102
EPA Contract No. 68-01-0759
TEMPO Project 6311-E7H-01
Prepared for
OFFICE OF MONITORING
US ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, B.C. 20460
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FOREWORD: WHAT IS "WATER QUALITY"?
The term "pollution" is defined by Section 502(19) of Public Law 92-500,
the Federal Water Pollution Control Act Amendments of 1972, as "the
man-made or man-induced alteration of the chemical, physical, bio-
logical, and radiological integrity of water. " But what is meant by
"water quality"?
Perhaps the best and almost certainly the most picturesque discussion
of the elusive definition of water quality is provided by P. H. McGauhey
(1968):
"The idea that 'quality' is a dimension of water that
requires measurement in precise numbers is of quite
recent origin. Ancient British common law . . . was
content to state that the user of water was not entitled
to diminish it in quality. But the question of what con-
stituted quality was neither posed nor answered. ... A
precise definition of •water quality lay a long way in the
future.
"More than half a century ago a Mississippi jurist said,
'It is not necessary to weigh with care the testimony of
experts — any common mortal knows when water is fit
to drink. ' Today we find it necessary to enquire of both
common mortal and water expert just how it is that we
know when water is fit for drinking. Moreover, in the
intervening years, interest in the 'fitness1 of water has
gone beyond the health factor and we are forced to decide
upon its suitability for a whole spectrum of beneficial use
involving psychological and social, as well as physio-
logical goals.
"Looking back on the history of water resource develop-
ment, one is impressed that under pioneer conditions it
was usually sufficient to define water quality in qualita-
tive terms, generally as gross absolutes. In such a
climate, terms such as swampwater, bilgewater, stump-
water, blackwater, sweetwater, etc. , produced by a free
combination of words in the English language, all con-
veyed meaning to the citizen going about his daily life.
'Fresh' as contrasted with 'salt' water was a common
differentiation arising from both ignorance and a limited
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need to dispel it. If a ground or surface water was fresh,
as measured by the human senses rather than the analyti-
cal techniques of chemists and biologists, it little occurred
to the user that it was any different than rainfall in produc-
ing crops. The Lord has the sun at his disposal whereas
the farmer has to rely upon ingenuity and hard labor to
deliver the water; but delivery rather than content of the
delivered product occupied attention. Thus the pioneer in
search of water for his agricultural needs was content
with a crude definition of its quality.
"As the author has noted elsewhere (McGauhey, 1961;
1965)
"A need to quantitate, or give numerical values to, the
dimension of water known as 'quality' derives from almost
every aspect of modern industrialized society. For the
sake of man's health we require by law that his water sup-
ply be 'pure, wholesome, and potable. ' The productivity
and variety of modern scientific agriculture require that
the sensitivity of hundreds of plants to dissolved minerals
in water be known and either water quality or nature of
crop controlled accordingly. The quantity of irrigation
water to be supplied to a soil varies with its dissolved
solids content, as does the usefulness of irrigation drain-
age waters. Textiles, paper, brewing, and dozens of
other industries using water each have their own peculiar
water quality needs. Aquatic life and human recreation
have limits of acceptable quality. In many instances water
is one of the raw materials the quality of which must be
precisely known and controlled.
"With these myriad activities . . . going on simultaneously
and intensively, each drawing upon a common water
resource and returning its waste waters to the common
pool, it is evident to even the most casual observer that
water quality must be identifiable and capable of altera-
tion in quantitative terms if the word is to have any
meaning or be of any practical use.
"Thus it is that those unwilling to go along with the
Mississippi jurist must express quality in numerical terms.
"The identification of quality is not in itself an easy task,
even in the area of public health where efforts have been
most persistent. For example, the great waterborne
IV
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plagues that swept London in the middle of the nineteenth
century pointed up water quality as the culprit; yet it was
another quarter of a century before the germ theory of
disease was verified, and more than half a century
before the water quality requirements to meet it were
expressed in numbers. Even in 1904, when our Mississippi
jurist spoke, children still died of 'summer sickness1
(typhoid) often ascribed to such things as eating cherries
and drinking milk at the same meal; and scarcely a family
escaped the loss of one of its members by typhoid fever.
Yet when it came to defining the water quality needed to
avoid this, the best we could do was to place on some of
the 'fellow travelers' of the typhoid organism numerical
limits below which the probability of contracting the dis-
ease was acceptably small. Nor has this dilemma been
overcome. In 1965, an outbreak of intestinal disease at
Riverside, California, which afflicted more than 20, 000
people and caused several deaths, -was traced to a new-
comer (Salmonella typhimurium) in a water known to be
safe by 'experts' watching the coliform index. So once
again the search begins for a suitable description of
quality.
"A second dilemma which survived the struggles that
codified and institutionalized our concepts of water quan-
tity lies in the definition of the word 'quality. ' While the
dictionary may suggest that quality implies some sort of
positive attribute or virtue in water, the fact remains that
one water's virtue is another's vice. For example, a
water too rich in nutrients for discharge to a lake may be
highly welcome in irrigation; and pure distilled water
would be a pollutant to the aquatic life of a saline estuary.
Thus, after all the impurities in water have been cataloged
and quantified by the analyst, their significance can be
interpreted in reference to quality only relative to the needs
or tolerances of each beneficial area to which the water is
to be put.
"Shakespeare has said, 'The quality of mercy is not
strained. . . . ' And indeed it is not as long as mercy is
defined in qualitative terms. One can but imagine the prob-
lems •which might arise if it were required that justice be
tempered with 1. 16 quanta of mercy in one case and 100
quanta in another. Yet this is precisely what confronts us
in establishing measures of the dimension of quality of
water. "
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References
1. McGauhey, P. H. , "Folklore in Water Quality Standards, " Civil
Engineering, Vol. 3, No. 6, New York, June (1965).
2. McGauhey, P. H. , "Quality — Water's Fourth Dimension,"
Proceedings of the Water Quality Conference, University of
California, Davis, California, January 11-13 (1961).
3. McGauhey, P. H. , Engineering Management of Water Quality,
McGraw-Hill Series in Sanitary Science and Water Resources
Engineering, McGraw-Hill, Inc., New York, New York '1968).
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ACKNOWLEDGEMENTS
The following TEMPO consultants and staff members wrote and
reviewed material for this report:
Mr. Harvey O. Banks, Belmont, California
Geraghty & Miller, Inc. , Port Washington, New York
Dr. David C. Kleinecke, TEMPO
Prof. P. H. McGauhey, El Cerrito, California
Mr. Charles F. Meyer, TEMPO (Project Manager)
Dr. Richard M. Tinlin, TEMPO
Dr. David K Todd, Berkeley, California
Mr. Edward J. Tschupp, TEMPO
Dr. Don L. Warner, Rolla, Missouri
Mr. H. Matthew Bills, Office of Monitoring, Environmental Protection
Agency, was the Program Element Manager. Technical direction and
guidance were provided by Mr. Donald B. Gilmore, Office of Monitor-
ing, who was the Program Element Director; and by Messrs. R. Kent
Ballentine, Robert R. Aitken, Clinton W. Hall, and Robert C. Scott,
Office of Water Programs, EPA.
VI1
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CONTENTS
Page
FOREWORD: WHAT IS "WATER QUALITY"? iii
References vi
ACKNOWLEDGEMENTS vii
ILLUSTRATIONS xv
TABLES xviii
SECTION I — INTRODUCTION 1- 1
SCOPE 1 1
Public Law 92-500 1-1
Contractual Requirement 1-1
APPROACH 1-3
GROUNDWATER QUALITY AND POLLUTION 1-5
Occurrence of Groundwater 1-5
Control by Elimination of Pollution Sources 1-6
Control by Desalination of Pollution Sources 1-7
Urbanization and Pollution 1-8
Hydrogeological Investigations 1-8
Time Frame of Pollution 1-11
Reference Materials 1-11
INSTITUTIONAL AND LEGAL ASPECTS 1 13
Disposal of Pollutants 1-13
Water Rights 1-14
Groundwater Management 1-17
References 1-24
SECTION II — INJECTION WELLS INTO
SALINE WATER AQUIFERS 2-1
INTRODUCTION 2-1
INDUSTRIAL INJECTION WELLS 2-1
Current Situation 2-2
Environmental Consequences 2-7
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Control Methods 2-10
Monitoring Procedures 2-28
State Programs 2-29
OTHER WELLS 2-33
PETROLEUM INDUSTRY WELLS 2-33
WELLS USED IN SOLUTION MINING 2-36
GEOTHERMAL ENERGY WELLS 2-37
WELLS FOR INJECTION OF SEWAGE EFFLUENT
AND DESALINATION PLANT BRINES 2-38
RADIOACTIVE WASTE DISPOSAL WELLS 2-39
GAS STORAGE WELLS 2-40
References 2-41
INJECTION WELLS INTO FRESHWATER AQUIFERS 2-45
Scope of the Problem 2-45
Environmental Consequences 2-47
Nature of Pollutants 2-48
Pollution Movement 2-51
Examples of the Use of Injection Wells 2-53
Control Methods 2-55
Monitoring Procedures 2-57
References 2-58
LAGOONS, BASINS, PITS 2-60
Use of Lagoons, Basins, and Pits 2-60
Scope of Problem 2-61
Potential Hazard to Ground-water 2-62
Control Methods 2-65
Monitoring Procedures 2-66
References 2-67
SEPTIC SYSTEMS 2-69
Scope of the Problem 2-69
History of Septic Systems 2-71
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Environmental Consequences 2-72
Control Methods 2-76
Monitoring Procedures 2-79
References 2-81
SPRAYING 2-82
History 2-82
Environmental Consequences 2-82
Future Prospects 2-87
Control Methods 2-88
References 2-90
STREAM BEDS 2-92
Scope of the Problem 2-92
Environmental Consequences 2-93
Nature of the Pollutants 2-94
Pollution Movement 2-94
Control Methods 2-95
Monitoring Procedures 2-98
References 2-99
LANDFILLS 2-100
The Matter of Definition 2-100
Environmental Consequences 2-101
Leaching of Landfills 2-103
Nature and Amount of Leachate 2-107
Control Methods 2-112
Monitoring Procedures 2-116
References 2-118
SECTION III — INDIRECT DISPOSAL OF POLLUTANTS 3-1
SEWER LEAKAGE 3-1
Scope of the Problem 3-1
Causal Factors 3-1
XI
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Environmental Consequences 3-2
Control Methods 3-4
Monitoring Procedures 3-5
TANK AND PIPELINE LEAKAGE 3-6
Scope of the Problem 3-6
Radioactive Wastes 3-6
History 3-7
Leakage in the United States 3-7
Environmental Consequences 3-10
Causal Factors 3-11
Pollution Movement 3-13
Control Methods 3-18
Monitoring Procedures 3-Z5
References 3-29
SURFACE WATERS 3-31
Scope of the Problem 3-31
Environmental Consequences 3-31
Pollution Movement 3-35
Control Methods 3-39
Monitoring Procedures 3-39
References 3-40
THE ATMOSPHERE 3-42
Scope of the Problem 3-42
Nature of the Pollutants 3-42
Pollution Movement 3-44
Control Methods 3-45
Monitoring Procedures 3-46
References 3-46
SECTION IV — SALT WATER INTRUSION 4-1
SEA WATER IN COASTAL AQUIFERS 4-1
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Scope of the Problem 4-1
History 4-1
Intrusion in the United States 4-2
Environmental Consequences 4-3
Causal Factors 4-3
Pollution Movement 4-4
Control Methods 4-5
Monitoring Procedures 4-11
References 4-12
SALINE WATER IN INLAND AQUIFERS 4-14
Scope of the Problem 4-14
Intrusion in the United States 4-15
Environmental Consequences 4-15
Causal Factors 4-15
Pollution Movement 4-19
Control Methods 4-21
Monitoring Procedures 4-24
References 4-26
SECTION V — POLLUTION FROM DIVERSION OF FLOW 5-1
EFFECTS OF URBAN AREAS 5-1
Scope of the Problem 5-1
Environmental Consequences 5-2
Road Salts 5-5
Sources and Nature of Pollutants 5-7
Pollution Movement 5-7
Control Methods 5-9
Monitoring Procedures 5-10
References 5-11
EFFECTS OF WATER CONTROL STRUCTURES 5-14
Dams 5-14
Xlll
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Levees 5-16
Channels 5-17
Flood-ways or Bypass Channels 5-19
Causeways 5-20
Flow Diversion Facilities 5-20
Sewers 5-20
SPILLS OF LIQUID POLLUTANTS 5-22
Scope of the Problem 5-22
Environmental Consequences 5-23
Pollution Movement 5-24
Control Methods 5-25
Monitoring Procedures 5-26
References 5-27
LAND SURFACE CHANGES 5-28
Introduction 5-28
Collapse — The Sinkhole Problem 5-28
Subsidence — The Arsenic Problem 5-30
References 5-35
UPSTREAM ACTIVITIES 5-36
Scope of the Problem 5-36
Causal Factors 5-36
Environmental Consequences 5-37
Control Methods 5-41
Reference 5-42
GROUNDWATER BASIN MANAGEMENT 5_43
Concept 5-43
Procedure 5-44
Sources of Basin Pollution 5-45
Control Methods 5-46
References 5-48
xiv
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ILLUSTRATIONS
Figure Title
2-1 Geologic features significant in deep waste-injection
well-site evaluation, and locations of industrial-waste
injection systems (Warner, 1968).
2-2 Schematic diagram of an industrial waste injection 2-24
well completed in competent sandstone (modified after
Warner, 1965).
2-3 Diagram of domestic sewage disposal system employing 2-46
a disposal well in the middle Deschutes Basin, Oregon
(Sceva, 1968).
2-4 Hypothetical pattern of flow of contaminated water 2-52
(shaded) injected through wells into water table and
artesian aquifers (Deutsch, 1963).
2-5 The wastewater renovation and conservation cycle 2-85
(Parizek, et al, 1967).
2-6 Schematic of various types of monitoring installations 2-86
(Parizek, et al, 1967).
2-7 Pattern of flow at and beneath a liquid waste-disposal 2-95
area in a dry stream bed. Shaded area shows hypo-
thetical path of movement of the contaminated water.
Arrows indicate the direction of groundwater flow.
3-1 Generalized shapes of spreading cones of oil at 3-14
immobile saturation (Comm. on Environmental
Affairs, 1972).
3-2 Movement of oil away from a spill area under the 3-15
influence of a water table gradient (Comm. on
Environmental Affairs, 1972).
3-3 Area contaminated by subsurface gasoline leakage and 3-16
groundwater contours in the vicinity of Forest Lawn
Cemetery, Los Angeles County, as of 1971 (Williams
and Wilder, 1971).
3-4 Illustration of the possible migration of an oil spillage 3-17
along an impermeable layer, to an outcrop, and hence
to a second spill location (Comm. on Environmental
Affairs, 1972).
3-5 Experimental results from Switzerland on the distri- 3-20
bution of oil in soil as a function of time (Todd, 1973).
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Figure Title
3-6 Swedish two-pump method for removal of oil
pollution from a well (Todd, 1973).
3-7 Oil moving with shallow groundwater is intercepted 3-23
by a ditch constructed across migration path (Comm.
on Environmental Affairs, 1972).
3-8 Three systems for skimming oil from a water surface 3-24
in ditches or wells (Comm. on Environmental Affairs,
1972).
3-9 Diagram showing how contaminated water is induced 3-32
to flow from a surface source to a pumped well.
Arrows show the direction of groundwater flow
(Deutsch, 1963).
3-10 Section across the Ohio River near Louisville, 3-36
Kentucky, showing the distribution of lines of equal
temperature of water during a pumping test of a well.
Note downward movement of warm water from the
river toward the pumped well (Rorabaugh, 1956).
3-11 Relation of the pattern of groundwater flow to the 3-37
occurrence and dilution of plating wastes in
Massapequa Creek, South Farmingdale, Long Island,
New York (Perlmutter and Lieber, 1970).
3-12 Average content and daily load of nitrate in water at 3-38
gaging stations on selected gaining streams in
sewered and unsewered areas, southern Nassau
County, Long Island, New York, 1966-70 (Perlmutter
and Koch, 1972).
4-1 Schematic vertical cross section showing freshwater 4-5
and sea water circulations with a transition zone.
4-2 Control of sea water intrusion in a confined aquifer 4-6
by shifting pumping wells from (a) near the coast to
(b) an inland location (Todd, 1959).
4-3 Control of sea water intrusion by a line of recharge 4-7
wells to create a pressure ridge paralleling the coast
(Todd, 1959).
4-4 Control of sea water intrusion by a line of pumping 4-8
wells creating a trough paralleling the coast (Todd,
1959).
xvi
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Figure Title Page
4-5 Control of sea water intrusion by a combination 4-9
injection-extraction barrier using parallel lines of
pumping and recharge wells (California Department
of Water Resources, 1966).
4-6 Control of sea water intrusion by construction of an 4-10
impermeable subsurface barrier (California
Department of Water Resources, 1966).
4-7 Schematic diagram of upconing of underlying saline 4-17
water to a pumping well.
4-8 Diagram showing upward migration of saline water 4-18
caused by lowering of water levels in a gaining
stream (Deutsch, 1963).
4-9 Diagram showing interformational leakage by 4-19
vertical movement of water through wells where the
piezometric surface lies above the water table
(Deutsch, 1963).
4-10 Illustrative sketch showing four mechanisms producing 4-20
saline water intrusion in Southern Alameda County,
California (California Department of Water Resources,
1960).
4-11 Monthly variations of total draft and chloride content 4-23
in a nearby observation well, Honolulu aquifer (Todd
and Meyer, 1971).
5-1 Hydrogeochemical sections oblique to the direction of 5-4
groundwater flow, showing lines of equal concentration
of MBAS in Nassau County, Long Island, New York.
Contaminated water is shaded; lower limit shown at
about 0. 1 mg/liter (Perlmutter, et al, 1964).
5-2 Flow pattern showing downward leaching of contami- 5-6
nants from a salt stockpile and movement toward a
pumped well (Deutsch, 1963).
5-3 Schematic diagram of water movement and land sub- 5-33
sidence when the piezometric surface of an aquifer
confined by a clay layer is lowered. The letter "O"
refers to the original position and "P" to the present
position.
xvn
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TABLES
Table Title Page
2-1 Distribution of existing industrial wastewater 2-4
injection wells among the 22 states having such
wells in 1972 (Warner, 1972).
2-2 Distribution of injection wells by industry type 2-4
(Warner, 1972).
2-3 Operational status of industrial injection wells 2-4
(Warner, 1972).
2-4 Total depth of industrial injection wells (Warner, 2-5
1972).
2-5 Rate of injection in industrial wells (Warner, 1972). 2-5
2-6 Pressure at which waste is injected in industrial 2-5
wells (Warner, 1972).
2-7 Type of rock used for injection by industrial wells 2-6
(Warner, 1972).
2-8 Age of injection zone of industrial wells (Warner, 2-6
1972).
2-9 Factors for consideration in the geologic and hydro- 2-14
logic evaluation of a site for deep-well industrial
waste injection.
2-10 Factors to be considered in evaluating the suitability 2-18
of untreated industrial -wastes for deep-well disposal.
2-11 Summary of information desired in subsurface 2-23
evaluation of disposal horizon and methods available
for evaluation.
2-12 Selected chemical-quality characteristics of native 2-50
water and tertiary treated injection water (Vecchiolo
and Ku, 1972).
2-13 Groundwater composition before and after spray 2-84
irrigation with sewage (Larson, I960).
2-14 Components of domestic solid waste (expressed as 2-102
percentages of total).
2-15 Landfill disposal of chemical process wastes. 2-103
2-16 Composition of muncipal refuse. 2-104
2-17 Leachate composition. 2-108
XVlll
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Table Title Page
2-18 Change in leachate analysis with time (Meichtry, 2-110
1971).
2-19 Groundwater quality. 2-116
3-1 Summary of interstate liquid pipeline accidents for 3-9
1971 (Office of Pipeline Safety, 1972).
3-2 Range of annual pipeline leak losses reported on 3-10
DoT Form 7000-1 for the period 1968 through 1971.
3-3 Frequency of causes of pipeline leaks in 1971 (Office 3-12
of Pipeline Safety, 1972).
3-4 Examples of constituents in stormwater runoff 3-33
(Federal Water Pollution Control Agency, 1969).
3-5 Chemical composition of rainwater at various 3-43
localities in the United States (Carroll, 1962).
3-6 Annual emissions of air pollution constituents in the 3-44
United States (Federal Water Pollution Control
Agency, 1969).
3-7 Concentrations of selected particulate contaminants 3-45
in the atmosphere in the United States from 1957 to
1961 (Federal Water Pollution Control Agency, 1969).
5-1 Summary of urban groundwater pollutants. 5-8
5-2 Description of areas of major land subsidence due to 5-31
groundwater extraction in the United States (Inter-
national Association of Scientific Hydrology, 1970).
5-3 Outline of a groundwater basin management study 5-44
(Comm. on Ground Water, 1972).
xix
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SECTION I
INTRODUCTION
SCOPE
Public Law 92-500
Section 304(e) of Public Law 92-500, the Federal Water Pollution
Control Act Amendments of 1972, provides that
"The Administrator [of EPAj . . . 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 extend of non-
point sources of pollutants, and (2) processes, procedures,
and methods to control pollution resulting from —
"(A) agricultural and silvicultural activities, including run-
off from fields and crop and forest lands;
"(B) mining activities, including runoff and siltation from
new, currently operating, and abandoned surface and
underground mines;
"(C) all construction activity, including runoff from the
facilities resulting from such construction;
"(D) the disposal of pollutants in wells or in subsurface
excavations;
"(E) salt water intrusion resulting from reductions of fresh
water flow from any cause, including extraction of ground-
water, irrigation, obstruction, and diversion; and
"(F) changes in the movement, flow, or circulation of any
navigable waters or groundwaters, including changes caused
by the construction of dams, levees, channels, causeways,
or flow diversion facilities. . . "
Contractual Requirement
Task 4 was added to TEMPO'S EPA contract on January 18, 1973.
Under Task 4, TEMPO is required to provide information for developing
EPA guidelines/reports in compliance with groundwater aspects of
Section 304(e)(2)D, E, and F of the Federal Water Pollution Control Act
Amendments of 1972, excluding surface-water aspects. This report is
submitted in satisfaction of the requirements of the following sub-tasks:
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"4A. Identify sources and evaluate the relative importance
of point and nonpoint sources of groundwater pollution
applicable to Section 304(e)(2)D, E, and F.
"4B. Identify and evaluate available processes, procedures,
and methods for control of groundwater pollution from
the sources identified under Task 4A . . .
"4C. Conclusions and recommendations, including discussion
of technological reasons and, to a lesser extent, related
legal, economic, and institutional factors. "
An informal smooth-draft report setting forth the results of work
accomplished under Tasks 4A, 4B, and 4C is to be submitted by June 1,
1973.
As indicated above, the sources and causes of pollution covered in this
report are limited to those included under parts D, E, and F of Section
304(e)(2). Guidelines, Section 304(e) (1), are not included; surface-
water aspects are not addressed; only the groundwater-pollution aspects
of parts D, E, and F are considered.
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APPROACH
A broad interpretation of parts D, E, and F was adopted, in accordance
with EPA guidance, in listing and defining the specific topics to be
covered.
To supplement TEMPO'S staff, a group of eminent consultants was
assembled. The resulting TEMPO team is listed in the Acknowledge-
ments. It includes both the depth and the breadth to prepare authorita-
tive material covering each topic. Team members not only authored
material in their own fields of expertise but also reviewed and contrib-
uted to the material written by other team members.
Several drafts were prepared; successive drafts were submitted to
EPA for review and comment, discussed in numerous meetings with
EPA personnel and among the TEMPO team members, and modified
accordingly. The material was then edited to achieve as much uniform-
ity of style as possible in this interim report. In view of the blending
of many inputs, and because of the editorial license that has been exer-
cised, the authors are not specifically identified here with their sub-
sections.
The treatment of each topic is not intended to be 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 lib-
eral use of selected references to more detailed explanations. The
material may be expanded or otherwise revised at a later date, in
accordance with the wishes of EPA.
Sections II and III of this report cover part D of Section 304(e)(2) of P. L.
92-500; Section IV covers part E; and Section V covers part F. Some
overlap exists, because each section and subsection is as self-contained
and independent as possible. References are included with each sub-
section.
1-3
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The remainder of Section I includes, immediately below, a general
discussion of groundwater quality and pollution, followed by a discus-
sion of institutional and legal aspects of groundwater pollution control,
1-4
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GROUNDWATER QUALITY AND POLLUTION
The quality of ground-water refers to its chemical, physical, and
biological characteristics. All groundwaters contain dissolved solids,
all possess physical characteristics such as temperature, taste, and
odor, and some contain biological organisms such as bacteria. The
natural quality of groundwater depends upon its environment,
movement, and source. In general, groundwater quality tends to be
relatively uniform within a given aquifer or basin, both with respect to
location and time.. But in different localities major contrasts in natural
quality can be noted. Thus, groundwater temperatures may range from
a few degrees above freezing in cold climates to the boiling point in
thermal springs, while salinities may range from near zero in newly
infiltrated precipitation to several hundred thousand milligrams per
liter in underground brines.
For the purposes of this report, groundwater pollution is defined as the
man-induced degradation of the natural quality of groundwater. The
particular use to which a groundwater can be placed depends, of course,
upon its quality. However, the various criteria defining the suitability
of a groundwater 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 groundwater.
This may take the form, for example, of an increase in chloride con-
tent, of a rise in temperature, or of the addition of E. coli bacteria.
Programs to control groundwater pollution are based upon the growing
realization that both groundwater and the underground space in which it
is stored are valuable natural resources to be conserved by preventing,
reducing, and eliminating pollution.
Occurrence of Groundwater
Groundwater forms a part of the hydrologic cycle. It originates as
precipitation or surface water before penetrating below the ground
1-5
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surface. Groundwater moves underground toward a natural discharge
point such as a stream, a spring, a lake, or the sea, or toward an
artificial outlet constructed by man such as a well or a drain.
Aquifers are permeable geologic formations capable of storing and
transmitting significant quantities of groundwater. The most common
aquifers are those consisting of unconsolidated alluvial materials such
as gravel, sand, silt, and clay. Other important aquifers occur in
limestones and volcanic rocks.
A water table defines the level at which the groundwater is at
atmospheric pressure; below the water table the permeable soil or
rock is completely saturated with water. An unconfined aquifer is one
bounded by a water table, whereas a confined aquifer is under a pres-
sure greater than atmospheric due to overlying impermeable rock
strata.
Groundwater typically flows at rates of from 2 meters per year to 2
meters per day. Above the water table the flow direction is generally
downward, but below the water table in the main groundwater body, the
movement is nearly horizontal and governed by the local hydraulic
gradient. Once a pollutant is introduced into an aquifer it tends to move
in the same direction as the surrounding groundwater and at a velocity
equal to or less than that of the groundwater. With time and distance
traveled, pollutants decrease in concentration, resulting from dilution,
adsorption, decay (eg, radioactive isotopes), and death (eg, bacteria).
From a point source of pollution, a plume is often detected extending
downstream within the aquifer and gradually dissipating with distance.
Control by Elimination of Pollution Sources
For any source or cause of pollution, an obvious control method would
be to eliminate entirely the source or the cause itself. This method,
however, is not possible in many situations and then becomes a trivial
solution. To illustrate the point, one method for controlling pollution
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from septic tanks would be simply to eliminate all septic tanks. To
completely eliminate the millions of septic tanks in the United States
would require alternatives that are not realistic or feasible. These
may include, for example:
• Installing sewer systems to replace septic tanks —
economically infeasible in many rural areas.
• Replacing septic tanks with individual home waste treat-
ment and desalination plants — technically and econom-
ically infeasible at the present time.
* Moving people to sewered areas — socially, legally, and
politically infeasible.
Thus, the control methods that are described for septic tanks include
not only the possibility of requiring sewers but also deal with regulating
their construction, their location as regards subsurface conditions and
topography, their density, their operation, and their maintenance. The
latter measures, while not eliminating groundwater pollution, •will
reduce it and will prevent it from exceeding prescribed levels.
The suggestion that the source or cause of pollution be eliminated is not
repeated for each of the sources and causes that are discussed. In
general, the control methods that are suggested and discussed are those
believed to be realistic and feasible. Clearly, the applicability of the
suggested methods will depend upon local situations.
Control by Desalination of Pollution Sources
The most extensive type of pollution affecting groundwater is increased
salinity (ie, mineralization). Many different pollution sources produce
much the same result. For example, industrial wastes, oilfield brines,
domestic and municipal sewage wastes, agricultural wastes, and irri-
gation return flows all contribute to increased mineralization of
groundwater.
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One method to control the impact of these and other sources on
groundwater quality would be to desalt the wastes before permitting
them to enter the ground. Although all of the salt from the pollutants
need not be removed, salinities would have to be reduced to a level
equal to or preferably less than that of the ambient groundwater before
recharging the treated water. But environmental, technical, and eco-
nomic considerations, at least in the near term future, may preclude
application of this procedure in most instances. For example, pro-
ducing the energy required for desalting, and disposing of the concen-
trated residual brine, may cause a severe environmental impact.
Urbanization and Pollution
The intensification effect of urban areas on groundwater pollution is an
important factor in considering the consequences of various sources of
pollution. Because man is responsible for actions leading to ground-
water pollution, it follows that a large proportion of the sources and
causes of underground pollution are found in and near population cen-
ters. This correlation between urbanization and pollution follows from
the fact that groundwater may be regarded as relatively stationary in
contrast to surface water flowing in streams. Furthermore, because
the diversity of man's activities that produce pollution are so concen-
trated in an urban environment, the sheer density of these pollution
opportunities becomes an important aspect of our modern pattern of
living.
One section of this report specifically addresses pollution from urban
areas. It describes those macroscopic facets of urban environments
which produce changes in surface and groundwater flows and, thereby,
changes in groundwater quality.
Hydrogeological Investigations
A fundamental concept applicable to almost all groundwater pollution
control situations is the need for comprehensive hydrogeological
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investigations before initiating control procedures. The geologic and
hydrologic environment of each groundwater resource system is
unique and far more complex and slower reacting than surface water
systems. The geologic structure governs the occurrence, the distri-
bution, and the amount of groundwater in storage; the direction and
rate of ground-water flow; the sources and locations of natural
recharges; and the locations of natural discharge. The local hydrology
largely determines the possible amounts of natural recharge. And
most importantly, the local geological characteristics determine the
movement, the dilution, and the adsorption of pollutants underground.
Groundwater resource systems are dynamic in nature. They respond
both in quantity and quality, albeit slowly, to natural phenomena such
as droughts. In relation to pollution control, man's activities such as
changes in land use, stream channel lining, and artificial recharge
produce significant influences. 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. A hydrogeological investigation is, therefore, essential to the
formulation of a comprehensive pollution control program for a ground-
water resource system. The areal extent and detail of the investigation
will depend upon the dimensions of the groundwater basin; the present
and prospective uses of the groundwater resources; the nature, loca-
tions, and characteristics of the sources or causes of pollution; and
the control measures required. An investigation in considerable detail
may be required solely to identify and evaluate the sources and causes
of pollution. Some control methods, such as sea water intrusion barri-
ers, require detailed studies of the geologic formations and the
hydraulic characteristics of aquifers.
A comprehensive hydrogeologic investigation should be designed to
yield requisite information on:
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• The geologic structure of the groundwater basin or aquifer
and its boundaries
• The nature and hydraulic characteristics of the subsurface
formations
• Groundwater levels, and directions and rates of groundwater
flow
• Groundwater in storage and usable storage capacity
• Groundwater quality
• Sources, locations, amounts, and quality of natural
recharge and discharge
• Locations, amounts, and quality of artificial recharge
• Land use
• Locations and amounts of extractions
• Quantity and quality of exports and imports
• Characteristics of known sources and causes of pollution.
This information is derived from a variety of investigative techniques
such as:
• Geologic reconnaissance
• Geophysical surveys
• Examination of well logs
• Test holes
• Pumping tests of wells
• Measurement of groundwater levels
• Analyses of groundwater, surface water, and wastewater
samples
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• Analyses of precipitation and runoff records.
Because of the dynamic nature of groundwater 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.
Time Frame of Pollution
An important aspect of groundwater is that once it is polluted, the effect
may remain for years, decades, or centuries. The average residence
time of a pollutant in groundwater is 200 years. The comparable resi-
dence time of a pollutant in a stream or river is 10 days. To remove
existing groundwater pollution is much more difficult than to remove
surface water pollution; groundwater pollution control is best achieved
by regulating the pollution source.
In many instances reduction or elimination of groundwater pollution
requires a two-pronged attack. One involves control of the pollution
source or cause. The other concerns measures to physically entrap
and, when feasible, to remove the polluted water from underground so
that the pollution will not spread and persist.
Reference Materials
Throughout this report references to readily available technical
literature have been included. These references amplify the informa-
tion presented and describe specific examples of the application of par-
ticular control measures. However, local groundwater pollution situa-
tions vary widely, even for the same type of pollution sources; conse-
quently, published material tends to describe individual case histories
rather than encompassing a broader viewpoint. In many cases a useful
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comprehensive single reference does not yet exist. This limitation
should be borne in mind in consulting any of the listed references.
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INSTITUTIONAL, AND LEGAL ASPECTS
Public Law 92-500 recognizes, as a policy of the Congress, the pri-
mary responsibility of the States to prevent, reduce, and eliminate
groundwater pollution. The Administrator of EPA is directed to develop
comprehensive programs for groundwater pollution control in coopera-
tion with State and local agencies and with other Federal agencies. Thus,
the laws and institutions relating to groundwater, and their adequacy,
are of basic importance. In most states, the functions of administra-
tion of •water rights and of •water pollution control are the responsibility
of different state agencies (Heath, 197Z). In California, both of these
are the responsibility of the State Water Resources Control Board, as
provided in the California Water Code (Divisions 2 and 7).
Institutional and legal aspects of the control of groundwater pollution
resulting from the activities listed in Section 304(e) (2) D, E, and F of
Public Law 92-500 are discussed here under three categories:
• Disposal of pollutants
• Other activities, many of'which involve water rights, which may
adversely affect ground water quality
• Groundwater management.
Disposal of Pollutants
The laws of the several states vary widely in their effectiveness for con-
trolling the disposal of pollutants to both surface and groundwater s; the
effectiveness of the state agencies administering those laws varies even
more widely (Hines, 1972). Under the Porter-Cologne Water Quality
Control Act in California (Division 7, Water Code), the State Water
Resources Control Board and the nine Regional Water Quality Control
Boards have adequate powers, including investigative and planning author-
ity, and do effectively control waste discharges which affect groundwaters
In Texas, control over groundwater pollution is divided between two
state agencies with differing objectives and policies and with a third
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agency involved. The Water Quality Board has broad authority to con-
trol pollution of groundwater (Chapter 21, Water Code), except as re-
gards the disposal of oil and gas waste which is the responsibility of
the Railroad Commission (Sec. 21.261, Water Code). The Texas Water
Development Board is responsible for investigating the quality of ground-
waters (Sec. 21.258, Water Code). Such fragmentation of authority
and responsibility is common.
At the present time, with few exceptions, the laws and institutions of
the states appear to be inadequate to control properly the disposal of
pollutants to groundwaters. The National Water Commission (1972)
recommended that regulation of groundwater quality by the states be
undertaken by the same agencies that regulate surface water quality.
The Commission further recommended that Federal legislation on con-
trol of surface water pollution be extended to include groundwater
pollution.
Water Rights
Any attempt to control an activity involving the diversion and use of
surface or groundwater s, in order to prevent groundwater pollution,
will involve vested water rights and usually will be in conflict with these
water rights. For many streams, groundwater basins, and aquifers
throughout the United States, rights to the full yield have long since
vested, either through actual diversion and use, or because of the ripar-
ian 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 constitu-
tional power to control the use of most of the surface waters of the
United States (Banks, 1967). 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
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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 (Banks, 1967). 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).
The Federal Government has never elected to assert these constitutional
powers over surface waters in a general manner except with respect to
control of pollution resulting from the 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 1944 (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, these have never passed beyond the committee stage. Up to
1973, therefore, responsibility for the allocation of water resources and
the granting and 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.
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To date, federal power over groundwater resources has been asserted
only in specific instances involving water supplies for federal installa-
tions (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 (Trelease, 1971, p 160).
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 (Davis, 1971). 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 (Meyers, 1971). Most of these
state laws are based on the objective of maximizing the economic
beneficial uses for municipal and industrial water supply, irrigation,
power 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 re-
sources. Generally, the hydrologic and hydraulic interrelationships
of surface waters and groundwaters are not recognized in state water
laws (Corker, 1971; National Water Commission, 1972).
Some states (Colorado, Florida, Indiana, Iowa, Minnesota, Nevada,
New Jersey, New Mexico, and Utah) have statutes governing the ex-
traction and use of groundwater. 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 groundwaters (Sec. 2100 et seq,
Water Code). Most groundwater laws have been laid down by the
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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. 2d798, 1955). Under the latter doctrine,
it is impossible to control the extraction and use of groundwater 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-
waters that might result from the diversion and use of either surface
or groundwater. State laws need to be revised and broadened, as has
been recommended by the National Water Commission (1972).
Groundwater Management
Groundwater management is not explicitly mentioned in Public Law
92-500, 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 groundwater quality. The many
interrelated sources and causes of groundwater pollution and the in-
herent complexity of groundwater 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 (Amer. Soc.
of Civil Engineers, 1972).
Groundwater management may be defined as the development and utiliza-
tion of the underground resources (water, storage capacity and trans-
mission capacity), frequently in conjunction with surface resources, in
a rational and, hopefully, optimal manner to achieve defined and
1-17
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accepted water resource development objectives. Quality as well as
quantity must be considered. The surface water resources involved
may include imported and reclaimed water as well as tributary streams
(Amer. Soc. of Civil Engineers, 1972; Corker, 1971; Mack, 1971;
Orlob and Bendy, 1973; Santa Ana Watershed Planning Agency, 1973).
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. Cur-
rent 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 groundwater pollution from sources and causes other than
waste disposal stem from these basic points:
• In most states, private ownership of groundwater attaches
through ownership of the land surface, and the 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 groundwater 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.
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When these three weaknesses are considered in their total ramifications,
it is evident that groundwater pollution control is possible only within
the context of a comprehensive management program for optimal alloca-
tion, conservation, protection, and use of the water together with re-
lated 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 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
those 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. Objec-
tives that might be important in one area, such as extending the life of
the groundwater aquifer, protecting spring flows, or controlling subsi-
dence, might have little relevance elsewhere. Many alternative institu-
tional structures could be considered for the management vehicle. But
the extremely diver se 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
structure would be universally applicable nor politically acceptable.
While management entities might not have the same organizational struc-
ture everywhere, certain geographic characteristics, fundamental re-
source information, and certain basic management powers and duties
are commonly required. Delineation of the geographic area to be
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encompassed by a workable management entity must include con-
sideration of areas having definable hydrologic boundaries. Further-
more, to the extent possible, the area should have social and economic
identity or common interests and be generally contiguous with existing
political subdivisions.
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 groundwater basin under various conditions can be
simulated or modelled mathematically, computerized management tools
have become available. Depending upon their intended use, these models
require adequate data (in appropriate formats and on a timely basis)
such as the following:
• Streamflow — 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.
• Areas, sources, rate and quality of groundwater recharge; sur-
face and groundwater inflow-outflow relationships; volume of
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aquifer storage capacity; aquifer transmissibility, specific
capacity, and boundaries; volume of surface water storage; sea-
sonal relationships of water demand and water in storage; rela-
tionships of surface and groundwater 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 manage-
ment 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 groundwaters. 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 groundwater
law; the law of waters should be a single, integrated body of
jurisprudence.
"Where surface and groundwater supplies are interrelated and
where it is hydrologically indicated, maximum use of the com-
bined resource should be accomplished by laws and regulations
authorizing or 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 groundwater, 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 groundwater supplies conjunctive-
ly; to issue bonds and collect pump taxes and diversion charges;
to buy and sell water and water rights and real property neces-
sary for recharge programs; to store water in aquifers, create
saltwater barriers and reclaim or treat water; to extract water;
to sue in its own name and as representative of its members for
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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
groundwater aquifers from injury and should authorize
enforcement both by individual property owners who are
damaged and by public officials and management 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. Among these are the following:
• Where groundwater pumpage results in quality deterioration
(intrusion either horizontally or vertically of poorer quality
waters in response to altered pressure equilibrium), will the
power to levy pump taxes and diversion charges be an adequate
assurance of an equitable system of cost sharing where users
must forego a free choice between water sources? Would this
loss of a free choice constitute a "taking" of property without
due compensation? Would condemnation be required?
• Where groundwater quality has deteriorated due to sources and
causes other than waste disposal, who should have cause of
legal action— the surface owner after validation by the state
pollution control agency? by EPA? by the management entity?
Who must identify the source and evaluate the effects?
• Local zoning
Can zoning authority now vested in local entities be superim-
posed on or made compatible with a state or federally adminis-
tered surface disposal permit system where the proposed dis-
posal is on or tributary to a groundwater basin recharge area?
How can the effects of diffuse urban and agricultural runoff on
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recharge quantity and quality be controlled at the local level
within the framework of state or federal waste discharge
permits?
• Land use (related to "Local zoning")
For operations such as feed lots, and the use of agricultural
pesticides and herbicides, there may be a need for land use
codes administered at the state level that could be integrated
•with enforcement power for pollution control vested in a local
or regional entity. What effect would this have on regional
economies? on local or county tax bases?
• Interstate aquifers
How can common standards and enforcement incentives as
between states be assured?
Where an aquifer is wholly intra-state but is recharged in part
by an interstate stream, how do the states interact?
What is the federal interest in either case, that of primary en-
forcer, concurrence in state programs (as in interstate compact
arrangements) or only in event of non-action by affected states?
If the latter, how is the action initiated?
• Artificial recharge
Must state water rights statutes be expanded (where now silent)
to include artificial recharge as a beneficial use?
Does the management entity have the right to store water under-
ground beneath private property and later recapture the water?
Or must the right be purchased or condemned?
These are difficult questions, which need to be resolved on a nationwide
basis. For purposes of this discussion, it is assumed that the present
relationship between state and federal jurisdiction in water matters will
continue. Even so, the Congress and state legislatures will need to
clarify a number of areas.
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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. O. , 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. Corker, C. E. , Ground-water Law, Management and Administration,
National Water Commission, Report No. NWC-L-72-026, NTIS
Accession No. PB 205 527, 509 pp (1971).
4. 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).
5. 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)
6. 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).
7. Mack, E. , Ground-water Management, National Water Commission,
Rept. NWC-EES-71-004, NTIS Accession No. PB 201 536, 179 pp
(1971).
8. Meyers, C. J. , Functional Analysis of Appropriation Law, National
Water Commission, Rept. NWC-L-71-006, NTIS Accession No.
PB 202 611, 72 pp (1971).
9. National Water Commission, Review Draft of Proposed Report,
2 vols. , 1127 pp. (1972).
10. Orlob, G. T. , and Bendy, B. B., "Systems Approach to Water
Quality Management, " Jour. Hydraulics Div. , Amer. Soc. of Civil
Engineers, vol. 99, no. HY 4, pp 573-587 (1973).
11. Santa Ana Watershed Planning Agency, California, Final Report to
Environmental Protection Agency (1973).
12. Trelease, F. J. , Federal-State Relations in Water Law, National
Water Commission, Rept. NWC-L-71-014, NTIS Accession No.
PB 203 600, 357 pp. (1971).
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SECTION II
INJECTION WELLS INTO
SALINE WATER AQUIFERS
INTRODUCTION
This section considers wells for injection of wastewaters into aquifers
containing saline "water. Primary emphasis is placed upon disposal of
industrial wastewater s; wells for this purpose are a relatively recent
development, and currently are receiving increasing attention in view
of their attractiveness as a possible disposal mechanism in selected
locations and under certain operating conditions. The discussion of
industrial wells is, therefore, considerably more extensive and de-
tailed than is found in other sections.
Wells for disposal of other types of wastes, such as oilfield brines,
sewage, and radioactive wastes, are treated later in this section. In
addition, other kinds of injection wells which may affect groundwater
pollution, including wells for solution mining, geothermal •wells, and
gas storage wells, are briefly described.
INDUSTRIAL INJECTION WELLS
The potential of wells for subsurface disposal of industrial wastes was
first recognized and implemented by at least one industrial company
as early as the 1930's. However, the extent of such use was small un-
til the 1960's when increasing emphasis on "water pollution control
caused industrial companies to seek new alternatives for wastewater
disposal, including subsurface injection.
As of mid- 1972, at least 246 such wells had been constructed in the
United States (Warner, 1972). Although this is a relatively small
number, considerable concern has been expressed about the use of
injection wells. Among the technical reasons for this concern are the
following:
2-
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• Some of the waste-waters that are being injected contain chemicals
that are relatively toxic and will persist indefinitely in the sub-
surface environment
• Monitoring of the subsurface environment is quite difficult in
comparison with monitoring of the surface
• If contamination of usable groundwater or other resources should
occur, decontamination may be difficult or impossible to effect.
Why should such wells be used at all in view of these and other possible
objections? If the alternatives are examined that are available for ulti-
mate disposition of wastewaters containing dissolved inorganic chemi-
cals, relatively nondegradable dissolved organic chemicals, or combina-
tions of these, it is found that they are limited to disposal to the ocean,
disposal to the land surface, disposal to fresh waters, storage, inciner-
ation, recovery of the chemicals for reuse, or subsurface injection. Of
these alternatives, subsurface injection may be the most satisfactory in
some cases. The need for continuous re-evaluation of the problem of
ultimate disposition of such wastewaters may become even more pres-
sing as a result of the goals stated in PL 92-500, the Federal Water
Pollution Control Act Amendments of 1972.
The following subsections discuss trends in usage of industrial waste-
water injection wells in the United States, the environmental impacts of
such wells, and methods for control of groundwater pollution from such
wells.
Current Situation
An inventory of industrial wastewater injection wells in the United States
by Donaldson (1964) listed only 30 wells. Subsequent inventories by
Warner (1967), the Interstate Oil Compact Commission in 1968 (Ives
and Eddy, 1968) and Warner (1972) listed 110, 118, and 246 wells, re-
spectively. The 1972 data show that only 22 wells had been constructed
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before I960, and that about twice that number existed in 1964. Between
1964 and 1972 about 25 wells per year were constructed, on the average.
Table 2-1 lists the number of 'wells that had been constructed in each of
the 22 states having such wells as of 1972. Other statistical informa-
tion concerning the wells inventoried in 1972 is included in Tables 2-2
through 2- 8.
These tables are useful in establishing the total range and dominant
characteristics of wells that have been constructed. The data also show
that patterns existing in 1967 have persisted since then, and might,
therefore, be expected to continue. Some significant observations that
can be made from the tables are:
• More than 50 percent of existing wells have been constructed by
chemical, petrochemical, or pharmaceutical companies, and
about 25 percent by refineries and natural gas plants. These data
identify the dominant present and probable future industrial users
of injection wells.
• About 80 percent of wells that have been constructed are presently
operating or will be put into operation. Only 5 percent of 'wells
that have been constructed were initial failures and never operated.
Thus, the geologic success ratio of such wells is very high.
• About 75 percent of existing wells are between 2000 and 6000 feet
in total depth. Less than 10 percent of the wells are shallower
than 1000 feet. This fact tends to provide considerable assurance
of protection to usable groundwater resources.
• About 70 percent of present wells inject less than 200 gallons per
minute and 86 percent less than 400 gallons per minute. This
suggests the capacity that can be expected for most wells and re-
duces the need to consider wastewater streams that exceed these
amounts.
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Table 2-1. Distribution of existing industrial
waste-water injection wells among the
22 states having such wells in 1972
(Warner, 1972).
Alabama
California
Colorado
Florida
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Michigan
5
4
2
5
5
12
1
27
3
40
27
Nevada
New Mexico
New York
North Carolina
Ohio
Oklahoma
Pennsylvania
Texas
Tennessee
West Virginia
Wyoming
1
1
4
1
8
9
8
71
4
7
1
246
Table 2-2. Distribution of injection wells by
industry type (Warner, 1972).
Industry Type
Refineries and natural gas
plants
Chemical, petrochemical &
pharmaceutical companies
Metal product companies
Other
Percent of Wells
1967
22
50
7
21
1972
26
56
7
11
Table 2-3. Operational status of industrial
injection wells (Warner, 1972).
Initial failure (never operated)
Operation pending
Presently operating
Operation rare or suspended
Abandoned and plugged (after operating)
5%
13%
66%
11%
5%
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Table 2-4. Total depth of industrial
injection wells (Warner, 1972).
Total Well Depth
0 -
1, 000 -
2, 000 -
4, 000 -
6, 000 -
Over 12,
1, 000 Ft.
2, 000
4, 000
6, 000
12, 000
000
Percent of Wells
1967
7
29
22
31
9
2
1972
8
16
29
34
12
1
Table 2-5. Rate of injection in industrial
wells (Warner, 1972).
Injection Rate
0 — 50 gpm
50 - 100
100 - 200
200 - 400
400 - 800
Over 800
Percent of Wells
1967
27
17
25
26
4
1
1972
36
13
20
17
7
7
Table 2-6. Pressure at -which waste is injected
in industrial wells (Warner, 1972).
~njection Pressure
Gravity flow
Gravity - 150 psi
150 - 300
300 - 600
600 - 1, 500
Over 1, 500
Percent of Wells
1967
14
29
27
9
20
1
1972
27
22
14
16
18
3
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Table 2-7. Type of rock used for injection
by industrial wells (Warner, 1972).
Rock Type
Sand
Sandstone
Limestone and Dolomite
Other
Percent of Wells
1967
30
45
22
3
1972
36
25
35
4
Table 2-8. Age of injection zone of industrial
wells (Warner, 1972) .
Quaternary
Tertiary
Mesozoic
Permian — Mis sis sippian 15% }
Devonian - Silurian 15% ?
Ordovician — Cambrian 27%_J
Precambrian
3%
33%
6%
57%
1%
• Only about 3 percent of existing wells are injecting at well-head
pressures exceeding 1,500 psi. This information, in conjunction
with the range of depths of wells previously mentioned, is reas-
suring; it suggests that presently-operating wells are generally
injected at pressures compatible with well depth and that waste-
waters are generally being injected into naturally-occurring
porosity, rather than into continuously induced fractures.
Tables 2-7 and 2-8 can be interpreted to show the distribution of wells
by geologic provinces. The 36 percent of wells injecting into poorly
consolidated sands of Quaternary and Tertiary age are principally
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located in the Gulf Coastal Plain. The 57 percent of wells injecting into
consolidated sandstones and limestones of Paleozoic age are located in
certain interior geologic provinces. Further examination of other well
characteristics shows that there is a good correlation between the geo-
logic provice, depth, construction method, and performance of existing
wells, •which "will permit emphasis on selected locations, aquifers, and
construction and operating requirements in a national monitoring program.
Environmental Consequences
Tangible impacts of wastewater injection that can be predicted to occur
in every case are:
• Modification of the groundwater system
• Introduction into the subsurface of fluids with a chemical compo-
sition different from that of the natural fluids.
Tangible impacts that could occur in individual cases are:
• Degradation of high-quality groundwater
• Contamination of other resources, such as petroleum, coal, or
chemical brines
• Stimulation of earthquakes
• Chemical reaction between wastewater and natural water
• Chemical reaction between wastewater and rocks in the injection
interval.
The degree to which any of these impacts can be predicted and quantified
in advance depends on the individual situation. In the case of existing
permitted wells, significant adverse environmental effects are not anti-
cipated to occur, otherwise the regulatory authorities would not have
licensed the wells. Where untenable impacts have been anticipated, per-
mits have been denied.
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CONTAMINATION OF FRESH GROUNDWATER. The impact of greatest
concern to most regulatory agencies is that of contamination of potable
ground-water. This could occur where a well injects into a saline-water
aquifer by:
• Escape of wastewater through the well bore into a freshwater
aquifer because of insufficient casing, by corrosion, or by other
failure of the injection well casing.
• Vertical escape of injected wastewater, outside of the well casing,
from the injection zone into a freshwater aquifer.
• Vertical escape of injected wastewater from the injection zone
through confining beds that are inadequate because of high primary
permeability, solution channels, joints, faults, or induced
fractures.
• Vertical escape of injected wastewater from the injection zone
through other nearby deep wells that are improperly cemented
or plugged, or that have insufficient or corroded casing.
Direct contamination of fresh groundwater could also occur by lateral
travel of injected wastewater (from a region of saline water) to a region
of fresh water in the same aquifer. In most cases, the distances
involved and the low rates of travel of wastewater make the probability
of direct contamination very small.
Indirect contamination of fresh groundwater can also occur when in-
jected wastewater displaces saline formation water, causing it to flow
into a freshwater aquifer. Vertical flow of the saline water could be
through paths of natural or induced permeability in confining beds or
through other inadequately cased or plugged deep wells. If large volumes
of wastewater were injected near a freshwater-saline water interface,
such as occurs in many coastal aquifers and also in inland locations, the
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interface could be displaced with saline water replacing fresh water in
the zone of displacement. Ferris (1972) discusses this response of
hydrologic systems to -waste injection.
In most presently existing wells, the potential for direct contamination
of fresh groundwater is small because of the construction used in these
wells and because of the large vertical distance between the injection
zones and freshwater aquifers. The belief that the potential for this
type of contamination is small is supported by the few instances of
direct contamination that have been documented. The vertical or lateral
movement of saline water into freshwater aquifers as a result of in-
creased formation pressures can be expected to occur, but will be less
dramatic than direct contamination in most cases because the effects
will be dispersed and difficult to recognize.
CONTAMINATION OF OTHER SUBSURFACE RESOURCES. No instance
of contamination of other subsurface resources by injected industrial
wastewater has yet been reported. The fact that little evidence of degra-
dation of potable ground-water and Other resources by this type of in-
jected wastewater has been found should not be cause for relaxation of
vigilance in regulating and operating such wells. On the contrary, as
more -wells are constructed each year, regulation and operation must
be increasingly more sophisticated to maintain this record.
Chemical reaction between wastewater and formation minerals and
water is a possible problem in well operation, but does not present
much potential for environmental impact that would be of concern to the
public.
EARTHQUAKE STIMULATION. The exact geologic and hydrologic cir-
cumstances in -which earthquakes can be stimulated by waste-water in-
jection are not yet known. However, the general requirement is the
presence of a fault along which movement can be induced in an area
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• Surface equipment and programs for emergency procedures in
the event of malfunction, including rapid shut-off and standby
facilities; programs for long-term decontamination in areas of
important but not critical occurrences.
• Abandonment procedures for all wells.
• Monitoring programs for injection wells.
• Monitoring programs for aquifers.
REGIONAL GEOLOGIC CONSIDERATIONS. The suitability of a specific
injection-well site must be evaluated by a detailed analysis of local geol-
ogy, but generalizations based on regional geologic considerations can
be made concerning the suitability of certain areas for waste-injection
wells.
Synclinal basins (Figure 2-1) and the Atlantic and Gulf Coastal Plains
are particularly favorable sites for deep waste-injection wells because
they contain relatively thick sequences of saltwater-bear ing sedimentary
rocks and because commonly the subsurface geology of these basins is
relatively well known.
Just as major synclinal basins are geologically favorable sites for deep-
well injection, other areas may be generally unfavorable because the
sedimentary-rock cover is thin or absent. Extensive areas where rela-
tively impermeable igneous-intrusive and metamorphic rocks are ex-
posed at the surface are shown in Figure 2-1. With the possible ex-
ception of small parts, these areas can be eliminated from consideration
for waste injection. The exposure of igneous and metamorphic rocks in
the Arbuckle Mountains, Wichita Mountains, Llano and Ozark uplifts,
the exposures just south of the Canadian Shield, and other such ex-
posures are perhaps not extensive, but they are significant because the
sedimentary sequence thins toward them and the salinity of the forma-
tion waters decreases toward the outcrops around the exposures.
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ro
i—i
c\)
fjHapf/.v
• GEOLOGIC DETAIL M0T SHOWN
Figure 2-1. Geologic features significant in deep waste-injection well-site evaluation,
and locations of industrial-waste injection systems (Warner, 1968).
-------
Regions shown on Figure 2-1 where a thick volcanic sequence lies at th.
surface generally are not suitable for waste-injection wells. Although
volcanic rocks have fissures, fractures, and interbedded gravel that
will accept injected fluids, they contain fresh water.
The immense and geologically complex Basin and Range province is a
series of narrow basins and intervening, structurally positive ranges.
Some of the basins might provide waste-injection sites, but their geology
is mostly unknown and the cost of obtaining sufficient information to in-
sure safe construction of injection wells would be very great.
The geology of the West Coast is complex and not well known. Relatively
small Tertiary sedimentary basins in southern California yield large
quantities of oil and gas, and probably are geologically satisfactory sites
for waste-injection wells. There are similar basins along the coast of
northern California, Oregon, and Washington, but little is known about
their geology.
Areas not underlain by major basins or prominent geologic features may
be generally satisfactory for waste injection if they are underlain by a
sufficient thickness of sedimentary rocks that contain saline water, and
if potential injection zones are sealed from freshwater-bearing strata
by impermeable confining beds.
LOCAL SITE EVALUATION. An outline of the factors for consideration
in the evaluation of 'waste injection 'well sites is given in Table 2-9.
Experience has shown that nearly all types of rocks can, under favorable
circumstances, have sufficient porosity and permeability to yield or
accept large quantities of fluids. Sedimentary rocks, especially those
deposited in a marine environment, are most likely to have the geologic
characteristics suitable for waste-injection wells . These characteristics
are (1) an injection zone with sufficient permeability, porosity, thickness,
and areal extent to act as a liquid-storage reservoir at safe injection
2-1:
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Table 2-9. Factors for consideration in the geologic
and hydrologic evaluation of a site for deep-
well industrial waste injection.
Regional Geologic and Hydrologic Framework
• Structural geology
• Stratigraphic geology
• Groundwater geology
• Mineral resources
• Seismicity
ft Hydrodynamics
Local Geology and Geohydrology
• Structural geology
• Geologic description of sedimentary rock units
1. Lithology
2. Detailed description of potential injection horizons and
confining beds
a. Thickness and vertical and lateral distribution
b. Porosity (type and distribution as well as amount)
c. Permeability (same as b)
d. Chemical characteristics of reservoir fluids
3. Groundwater aquifers at the site and in the vicinity
a. Thickness
b. General character
c. Amount of use and potential for use
4. Mineral resources and their occurrence at the well site
and in the immediate area
a. Oil and gas (including past, present and possible
future development)
b. Coal (as in a)
c. Brines (as in a)
d. Other (as in a)
pressures, and (2) an injection zone that is vertically below the level of
freshwater circulation and is confined vertically by rocks that are, for
practical purposes, impermeable to waste liquids.
Vertical confinement of injected wastes is important not only for the pro-
tection of usable water resources, but also for the protection of developed
2-14
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and undeveloped deposits of hydrocarbons and other minerals. The
effect of lateral movement of waste on such natural resources also must
be considered.
Sandstone, limestone, and dolomite are commonly porous and permeable
enough in the unfractured state to be suitable injection zones. Naturally
fractured limestone, dolomite, shale, and other rocks also may be satis-
factory. Rocks with solution or fracture porosity may be preferable to
rocks with intergranular porosity, because commonly solution and frac-
ture flow channels are relatively" large in comparison to intergranular
pores and are not, therefore, as likely to be plugged by suspended solids
in the injected liquids. Waste injection into limestone and dolomite has
proved particularly successful in some places because the permeability
of these rocks can be improved greatly with acid treatment.
Unfractured shale, clay, slate, anhydrite, gypsum, marl, and bentonite
have been found to provide good seals against the upward flow of fluids.
Limestone and dolomite may be satisfactory confining strata; but these
rocks commonly contain fractures or solution channels, and their ade-
quacy must be determined carefully in each case.
The minimum depth of burial, the necessary thickness of confining
strata, and the minimum salinity of water in the injection zone have not
been established quantitatively, and it may be possible to specify these
constraints only for individual cases, as has been done in the past.
The minimum depth of burial can be considered to be the depth at which
a confined saline-water-bearing zone is present; it may range from a
few hundred to several thousand feet.
The minimum salinity of water in the injection zone probably will be
specified by regulatory agencies in most states, but will be at least
1, 000 mg of dissolved solids per liter of water except under unusual cir-
cumstances. Water containing less than 500 mgALnow is considered to
2-15
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be acceptable for potable water used by interstate carriers. Formerly,
if such water was not available, water containing 1, 000 mgAC of dissolved
solids was considered acceptable. The minimum salinity may be set at
a level higher than 1, 000 mg/-t of dissolved solids to provide a margin
of safety and because water with several times this dissolved-solids
content is used in certain areas for domestic, industrial, or agricultural
purposes.
Illinois agencies have determined that groundwater with a dissolved solids
content less than 10, 000 mg/'t should be protected. All groundwaters in
New York have been classified, based on quality. According to the New
York classification, waste injection is prohibited in aquifers containing
water with a dissolved solids content of 2, 000 mg/£ or less.
It has been found that a confining stratum only 10 to 20 feet thick may
provide a good seal to retain oil and gas. Such thin confining beds gen-
erally would not be satisfactory for containing injected waste because
they would be very susceptible to hydraulic fracturing, and even a small
fault could completely offset them vertically. Fortunately, in many
places hundreds or thousands of feet of impermeable strata enclose poten-
tial injection zones and virtually ensure their segregation.
The thickness and permeability necessary to allow fluid injection at the
desired injection rate can be estimated from equations developed by
petroleum engineers and groundwater hydrologists. The geometry of the
injection zone also determines its suitability for waste-injection. A
thick lens of highly permeable sandstone might not be satisfactory for
injection if it is small and surrounded by impermeable beds, because
pressure buildup in the lens would be rapid in comparison to that in a
"blanket" sandstone.
In addition to stratigraphy, structure, and rock properties, which are
factors routinely considered in subsurface studies, aquifer hydrodynamics
2-16
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may be significant in the evaluation of waste-injection well sites. The
presence of a natural hydrodynamic gradient in the injection zone will
cause the injected waste to be distributed asymmetrically about the well
bore and transported through the aquifer even after injection has ceased.
Hydrodynamic dispersion — the mixing of displacing and displaced fluids
during movement through porous media — may cause much wider distri-
bution of waste in the injection zone than otherwise would be anticipated.
Dispersion is known to occur in essentially homogeneous isotropic sand-
stone, and it could lead to particularly rapid lateral distribution of waste
in heterogeneous sandstone and fractured or cavernous strata. Sorption
of waste constituents by aquifer minerals retards the spread of waste
from the injection site.
Mathematical models now available are satisfactory for accurately pre-
dicting the moveme.it of waste in most natural aquifers only under re-
strictive, simplified physical circumstances. Even if knowledge of the
physics of fluid movement in natural aquifers were considerably more
advanced, the determination of the physical parameters that characterize
an injection zone would still be a problem if few subsurface data were
available. These restrictions do not, however, preclude the quantiative
estimation of the rate and direction of movement of injected waste.
The maximum pressure at •which liquids can be injected •without causing
hydraulic fracturing may be the factor limiting the intake rate and opera-
ting life of an injection well. The injection pressure at which hydraulic
fracturing will occur is related directly to the magnitude of regional rock
stress and the natural strength of the injection zone (Hubbert and Willis,
1957). In some areas, the pressure at which hydraulic fracturing will
occur can be estimated before drilling on the basis of experience in near-
by oil fields.
Other considerations in the determination of site suitability are (1) the
presence of abnorrra.lly high natural fluid pressure and temperature in
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the potential injection zone that may make injection difficult or uneco-
nomical; (2) the local incidence of earthquakes that can cause move-
ment along faults and damage to the subsurface well facilities; (3) the
presence of abandoned, improperly plugged wells that penetrate the
injection zone and provide a means for escape of injected waste to
groundwater aquifers or to the surface; (4) the mineralogy of the injec-
tion zone and chemistry of interstitial waters, which may determine the
injectability of a specific waste; and (5) the possibility that in technically
unstable areas, fluid injection may contribute to the occurrence of
earthquakes.
WASTEWATER EVALUATION. A foremost consideration in evaluating
the feasibility of wastewater injection is the character of the untreated
wastewater. Table 2-10 lists the pertinent factors.
The suitability of waste for subsurface injection depends on its volume
and physical and chemical properties of the potential injection zones and
their interstitial fluids.
Table 2-10. Factors to be considered in evaluating
the suitability of untreated industrial
wastes for deep-well disposal.
Volume
Physical Characteristics
1. Specific gravity
2. Temperature
3. Suspended solids content
4. Gas content
Chemical Characteristics
1. Chemical constituents
2. pH
3. Chemical stability
4. Reactivity
a. with system components
b. with formation waters
c. with formation minerals
'5. Toxicity
Biological Characteristics
2-18
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Waste disposal into subsurface aquifers constitutes the use of limited
storage space, and only concentrated, very objectionable, relatively
untreatable wastes should be considered for injection. The fluids in-
jected into deep aquifers do not occupy empty pores; each gallon of
waste will displace a gallon of the fluid which saturates the storage zone.
Optimal use of underground storage space will be realized by use of deep-
well injection only where (1) more satisfactory alternative methods of
waste treatment and disposal are not available and (2) minimization of
injected-waste volumes is achieved through good waste management.
The intake rate of an injection well is limited, and its operating life
may depend on the total quantity of fluid injected. The variable limiting
the injection rate or well life can be the injection pressure required to
dispose of the produced waste. Injection pressure is a limiting factor
because excessive pressure causes hydraulic fracturing and possible
consequent damage to confining strata, and the pressure capacity of
injection-well pumps, tubing, and casing is limited. In most states
maximum injection pressures are specified by regulatory agencies and
are seldom allowed to exceed about 0. 8 psi/ft of well depth. The initial
pressure required to inject waste at a specified rate and the rate at
which injection pressure increases with time can be calculated if the
physical properties of the aquifer and the waste are known. The intake
rate of most waste-inj ection wells now in use has been found to be less
than 400 gpm, but intake rates can be higher than this in particularly
favorable circumstances.
The operating life of an injection well may be related to the volume of
injected waste, because the distance injected waste can be allowed to
spread laterally may be restricted by law or by other considerations.
The storage volume or effective porosity in the vicinity of an injection
well can be computed very simply, but dispersion, adsorption, and chem-
ical reaction complicate the calculation of the distribution of injected
waste.
2-19
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The injectability of a particular waste depends on the physical and
chemical characteristics of the waste, the aquifer, and the native aqui-
fer fluids, because physical or chemical interactions between the waste
and the aquifer minerals or fluids can cause plugging of the aquifer
pores and consequent loss of intake capacity. Plugging can be caused
by suspended solids or entrained gas in the injected waste, reactions
between injected fluids and aquifer minerals, reactions between injected
and interstitial fluids, and autoreactivity of the waste at aquifer temper-
ature and pressure. Plugging at or near the well bore also can be
caused by bacteria and mold. Wastes that are not initially injectable
commonly can be treated to make them so.
Knowledge of the mineralogy of the aquifer and the chemistry of inter-
stitial fluids and waste should indicate the reactions to be anticipated
during injection. Laboratory tests can be performed with rock cores
and formation and wastewater samples to confirm anticipated reactions.
Selm and Hulse (1959) list the reactions between injected and interstitial
fluids that can cause the formation of plugging precipitates—(1) precipi-
tation of alkaline earth metals such as calcium, barium, strontium, and
magnesium as relatively insoluble carbonates, sulfates, orthophosphates,
fluorides, and hydroxides; (2) precipitation of metals such as iron, alum-
inum, cadmium, zinc, manganese, and chromium as insoluble carbonates
bicarbonates, hydroxides, orthophosphates, and sulfides; and (3) precipi-
tation of oxidation-reduction reaction products.
The plugging effect of such precipitates is not certain, but if plugging is
considered to be a possibility the waste can be treated to make it non-
reactive. Alternatively, nonreactive water can be injected ahead of the
waste to form a buffer between the waste and the aquifer water (Warner,
1966).
Common minerals that react significantly with wastes are the acid-
soluable carbonate minerals and the clay minerals. Acidizing of
2-20
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reservoirs containing carbonate minerals is an effective well-stimulation
technique, and reaction of acidic wastes with carbonate minerals thus
might be expected to be beneficial. An undesirable effect of the reaction
of acid waste with carbonate minerals could be evolution of CC>2 that
might increase pressure and cause plugging if present in excess of its
solubility. Roedder (1959) reported that the reaction of acid aluminum
nitrate waste with calcium carbonate results in a gelatinous precipitate
that could cause plugging.
Clay minerals are known to reduce the permeability of sandstone to
water in comparison to its permeability to air. The permeability of a
clay-bearing sandstone to water decreases with decreasing •water salinity,
decreasing the valence of the cations in solution, and increasing the pH
of the water.
Ostroff (1965) and Warner (1965, 1966) give additional references and
discussion concerning waste injectability. Factors that bear on waste
injectability, such as aquifer mineralogy, temperature and pressure, and
chemical quality of aquifer fluids, are a logical part of feasibility reports
because the treatment necessary to make a waste injectable can be an
important part of a total waste management program.
WELL CONSTRUCTION AND EVALUATION. The variability of geologic
situations and the characteristics of wastes precludes establishment of
rigid specifications for inject ion-•well construction. Each injection sys-
tem requires individual consideration with respect to waste volume and
type, and the geologic and hydrologic conditions that exist. Certain
general requirements, however, can be outlined.
Construction of -well facilities for an injection system includes drilling,
logging and testing, and completion activities. A hole must first be
drilled, logged, and tested before it can be ascertained that it should be
completed as an injection well. The completion phase includes installa-
tion and cementing of the casing, installation of injection tubing, and
Z-Z1
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other related procedures such as perforating or slotting the casing and
stimulating the injection horizon. Generally, it is necessary to install
and cement at least some of the casing during drilling.
Drilling programs should be designed to permit installation of the neces-
sary casing strings with sufficient space around the casing for an ade-
quate amount of cement. Samples of the rock formations penetrated
should be obtained during drilling. It may be necessary to have forma-
tion cores or water samples at horizons of particular importance to pro-
vide necssary geologic and hydrologic data. Complete logging and testing
of wells intended for injection should be required, and the data should be
filed with the appropriate state agency or agencies.
In Table 2-11 is summarized the information desired in subsurface
evaluation of the disposal horizon and the methods for obtaining this
information.
Design of a casing program depends primarily on well depth, character
of the rock sequence, fluid pressures, type of well completion, and the
corrosivenes s of the fluids that will contact the casing. Where fresh
groundwater supplies are present, a casing string (surface casing) is
usually installed to below the depth of the deepest groundwater aquifer
immediately after drilling through the aquifer (Figure 2-2). One or more
smaller-diameter casing strings are then set, with the bottom of the last
string just above or through the injection horizon, depending on whether
the hole is to be completed as an open hole or is to be cased, perforated,
and gravel-packed.
The annulus between the rock strata and the casing is filled with a cement
grout, to protect the casing from external corrosion, to increase casing
strength, to prevent mixing of the waters contained in the aquifers behind
the casing, and to forestall travel of the injected waste into aquifers
other than the disposal horizon. Neat portland cement (no sand or gravel)
is the basic material for cementing. Many additives have been developed
2-22
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Table 2-11. Summary of information desired in subsurface
evaluation of disposal horizon and methods
available for evaluation.
Information Desired
Porosity
Permeability
Fluid pressures in formations
Water samples
Geologic formations intersected
by hole
Thickness and character of
disposal horizon
Mineral content of formation
Temperature of formation
Amount of flow into various
horizons
Methods Available
for Evaluation
Cores, electric logs, radio-
active logs, sonic logs
Cores, pumping or injection
tests, electric logs
Drill stem tests, water level
measurements
Cores, drill stem tests
Drill time logs, drilling sam-
ples, cores, electric logs ,
radioactive logs, caliper logs
Same as above
Drilling samples, cores
Temperature log
Injectivity profile
to impart some particular quality to the cement. Additives can, for
example, be selected to give increased resistance to acid, sulfates,
pressure, temperature, shrinkage, and so forth.
Temperature logs, cement logs, and other well-logging techniques can
be required as a verification of the adequacy of the cementing. Cement
can be pres sure-tested if the adequacy of a seal is in question.
Waste should be injected through separate interior tubing rather than
being in contact .with the well casing. This is particularly important
when corrosive wastes are being injected. A packer can be set near the
bottom of the tubing to prevent corrosive waste from contacting the
casing. Additional corrosion protection can be provided by filling the
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FRESH-WATER-BEARING
SURFACE SANDS AND
GRAVELS
IMPERMEABLE SHALE
CONFINED FRESH-WATER-
BEAPING SANDSTONE
IMPERMEABLE
SHALE
\
\
\
\
\
\
/\
\
\
k\
PRESSURE GAGE
WELLHEAD PRESSURE
PRESSURE GAGE Opsi
NX
\ /
PERMEABLE SALT-WATER-
BEARING SANDSTONE
INJECTION HORIZON
- SURFACE CASING SEATED
-/ BELOW FRESH WATER AND
/' CEMENTED TO SURFACE
INNER CASING SEATED IN OR
ABOVE INJECTION HORIZON
AND CEMENTED TO SURFACE
INJECTION TUBING
ANNULUS FILLED WITH
NONCORROSIVE FLUID
PACKERS TO PREVENT FLUID
CIRCULATION IN ANNULUS
OPEN-HOLE COMPLETION IN
COMPETENT STRATA
IMPERMEABLE SHALE
Figure Z-2. Schematic diagram of an industrial waste
injection well completed in competent
sandstone (modified after Warner, 1965).
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annular space between the casing and the tubing with oil or water con-
taining an added corrosion inhibitor.
It is frequently desired to increase the acceptance rate of injection
wells by chemical or mechanical treatment of the injection zone. Care-
ful attention should be given to stimulation techniques such as hydraulic
fracturing, perforating, and acidizing to insure that only the desired
intervals are treated and that no damage to the casing, cement, or
confining beds occurs.
AQUIFER RESPONSE AND WASTEWATER MOVEMENT. Estimates of
the rate of pressure buildup in the receiving aquifer are important be-
cause the maximum pressure at which liquids can be injected may be
the factor limiting the intake rate and operating life of an injection well.
From data obtained during construction and testing of an injection well,
estimates can be made of the rate of increase of pressure in the re-
ceiving aquifer for a projected rate of wastewater injection. Van
Everdingen (1968) outlines the methodology for estimating the pressure
buildup resulting from injection wells.
Estimates of the lateral extent of wastewater movement are needed so
that the location of the underground space occupied by the wastewater
can be made a matter of record to be used in regulation and management
of the subsurface.
Estimates of the extent and direction of wastewater movement can be
made after the geohydrologic characteristics of the receiving aquifer
have been determined. This estimate is potentially very complex,
since the cylindrical pattern that can be assumed as the most elementary
case may be modified by the natural flow system in the aquifer, hydro-
dynamic dispersion, and density and viscosity differences between in-
jected and interstitial fluids.
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OPERATING PROGRAM. The operating program for an injection sys-
tem should conform with the geological and engineering properties of
the injection horizon and the volume and chemistry of the waste fluids.
Injection rates and pressures must be considered jointly, since the pres^
sure will usually depend on the volume being injected. Pressures are
limited to those values that will prevent damage to well facilities or to
the confining formations. The maximum bottom-hole injection pressure
is commonly specified on the basis of well depth. Regulatory agencies
have specified maximum allowable bottom-hole pressure of from about
0. 5 to 1.0 psi per foot of well depth, depending on geologic conditions,
but operating pressures are seldom allowed to exceed about 0. 8 psi per
foot of depth.
Experience with injection systems has shown that an operating schedule
involving rapid or extreme variations in injection rates, pressures, or
waste quality can damage the facilities. Consequently, provisions
should be made for shut-off in the event of hazardous flow rates, pres-
sure, or waste quality fluctuations.
SURFACE EQUIPMENT AND EMERGENCY PROCEDURES. Surface
equipment includes holding tanks and flow lines, filters, other treatment
equipment, pumps, monitoring devices, and standby facilities.
Surface equipment associated with an injection well should be compatible
with the waste volume and physical and chemical properties of the waste
to insure that the system will operate as efficiently and continuously as
possible. Experience with injection systems has revealed the difficul-
ties that may be encountered due to improperly selected filtration equip-
mand and corrosion of injection pumps.
Surface equipment should include well-head pressure and volume moni-
toring equipment, preferably of the continuous recording type. Where
injection tubing is used, it is advantageous to monitor the pressure of
2-26
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both the fluid in the tubing and in the annulus between the tubing and the
casing. Pressure monitoring of the annulus is a means of detecting
tubing or packer leaks. An automatic alarm system should signal the
failure of any important component of the injection system. Filters
should be equipped to indicate immediately the production of an effluent
with too great an amount of suspended solids.
Standby facilities are essential in order to cope with malfunction of a
well that might occur. In all cases, provision should be made for
alternative waste management facilities and procedures in the event of
injection system failure. Alternative facilities could be standby wells,
holding tanks, or a treatment plant.
In situations where the character of the wastewater being injected, or
other reasons, would dictate the need, additional facilities and procedures
could be available for use in the event of engineering failures of the sys-
tem or detection of contamination of a subsurface resource. For example,
handling of a particularly corrosive wastewater would be reason for
planning in advance the procedure to be used in the event that tubing
failure during operation was detected. Such a procedure might be to
begin immediately injection of a non-corrosive liquid into the well until
the v/ell bore was completely cleared, then to shut the well in until the
reservoir pressure had died away to a level that would allow removel of
the damaged tubing without backflow of the corrosive wastewater. Such
a procedure would help to prevent damage to the casing, packer, etc.
Injection of a radioactive wastewater would require establishment of
procedures for use during well workovers or any other handling of equip-
ment that might become contaminated.
Emergency procedures could also include notification of nearby users of
groundwater or other resources, should contamination be detected, or
even a program for aquifer rehabilitation.
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Monitoring Procedures
Monitoring can be performed on the injection system itself, in the in-
jection zone, or in aquifers above or below the injection zone.
Well-head pressure and waste injection rate should be continuously
measured. If injection tubing is used, the casing-tubing annulus should
be pressure monitored. Other types of monitoring include measure-
ment of the physical, chemical, and biological character of injected
fluids on a periodic or continuous basis, and periodic checking of the
casing and tubing for corrosion, scaling, or other defects.
The possible purposes in monitoring the injection zone or adjacent
aquifers are to determine fluid pressures and the rate and direction of
movement of the wastewater and aquifer fluids.
As discussed by Warner (1965), monitoring with wells to determine the
rate and extent of movement of wastewater within the injection zone is
of limited value because of the difficulty of intercepting the wastewater
front and of interpreting information that is obtained. For these rea-
sons, and because of the cost, few such monitor wells have been
constructed.
A more feasible approach is to monitor the fluid p'ressure in the injec-
tion zone or adjacent aquifers. A larger number of monitor wells have
been constructed for this purpose. Goolsby (1971) discusses an example
of an injection system where a monitor well was useful for both detec-
tion of waste travel and measurement of reservoir fluid pressure.
The most common type of monitor well used in conjunction with waste-
water injection systems is that constructed in the freshwater aquifers
near the injection well. If these wells are pumping wells, they provide
a means for detecting (eventually) leakage from the injection well or
injection horizon; pollutants entering the supply aquifer will tend to
move toward a discharging 'well.
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Changes in the quality of water in springs, streams, and lakes may
also be monitored to detect effects from waste disposal wells.
State Programs
The status of regulation of disposal wells at the state level is highly
variable. Most states that have significant oil production regulate the
disposal of oilfield water through an oil and gas agency, but other cate-
gories of disposal -wells are most frequently regulated through water
pollution control, environmental protection, or health agencies.
A few states have developed specific laws, regulations, or policies
concerning industrial wastewater injection. A chronological list of
these developments is given below:
1961 Texas — Injection well law adopted
1966 Kansas — Regulations adopted
1967 Ohio — Injection well law adopted
New York — Groundwater classified
1969 Indiana- "Test Hole" legislation enacted
Michigan — "Mineral Well Law" enacted
New York — Injection well policy established
Ohio Valley — Regulatory policy recommended
Texas — 1961 law amended
West Virginia — Injection well legislation enacted
1970 Illinois - Policy specified
FWPCA — Policy announced
Colorado — Rules and regulations for subsurface
disposal adopted
1971 Missouri - Disposal wells prohibited
1972 Oklahoma - Regulations adopted
Council of State Governments — Model State Toxic
Waste Disposal Act.
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Texas was the first state to pass a law specifically concerning indus-
trial wastewater injection wells, in 1961. Since that time, several
other states have passed similar laws or amended existing ones to in-
clude consideration of underground injection. Formal regulations have
been adopted by Colorado and Oklahoma. Formal or informal policy
guidelines have been specified by several states. With the exception of
the specific cases listed above, most states regulate injection wells
under general water pollution control laws, oil and gas laws, or both.
There is frequently overlapping jurisdiction among state agencies re-
garding such wells.
Because regulation of industrial wastewater injection wells is a rela-
tively new responsibility, the laws, regulations, and policies in this
area are in the developmental stage. During 1970—1972, an advisory
committee to the Ohio River Valley Water Sanitation Commission formu-
lated policies, procedures, and technical criteria for use by the eight
member states (Illinois, Indiana, Kentucky, New York, Ohio,
Pennsylvania, Virginia, and West Virginia). In January 1973, ORSANCO
formally adopted the Committee recommendations as Resolution 1-73,
incorporating eight steps:
1. Preliminary assessment by the applicant of the geology and geo-
hydrology at the proposed well site and the suitability of the
wastewater for injection. These initial studies should be made
in consultation with the appropriate state agencies.
Z. Application to the state agency with legal jurisdiction for per-
mission to drill and test a well for subsurface wastewater injec-
tion. The application must be supported by a report that docu-
ments all details of the proposed injection system, including
monitoring and emergency standby facilities. On issuance of a
permit, the applicant will be apprised of the geologic and geo-
hydrologic parameters that will be employed by the state in
2-30
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reaching its final determination on feasibility of wastewater
injection into the well, anticipated limitations on injection pres-
sure and injected volumes, the probable monitoring requirements,
and probable requirements for alternative •wastewater manage-
ment programs in the event that operational problems occur
during the use of the injection well.
3. Drilling and evaluation of the well and submission of samples,
logs, test information, and a well-completion report to the
state.
4. Request by the applicant for approval to inject wastewater into
the well. The request should indicate any changes from the
original plan in system construction and operating program.
5. Prompt evaluation by the state of the well and approval, approval-
with-modification, or disapproval of the proposed injection sys-
tem based on the geologic, geohydrologic, and engineering data
submitted. On approval, the applicant will be provided 'with
specific instructions and monitoring requirements.
6. Operation of the injection system in accordance with state re-
quirements. The appropriate regulatory agency should be noti-
fied immediately if operational problems occur, if remedial
•work is required, or if significant changes in the •wastewater
stream are anticipated.
7. Abandonment of the well in accordance with state regulations or
other technically acceptable procedures.
8. In addition to the seven steps listed above, where a proposed
injection well is to be located within five miles of a state border,
the appropriate agencies in the adjacent state should be provided
the opportunity to review and comment on the application. Fur-
ther, these agencies should be advised of any significant prob-
lems that occur during the operation of such a well.
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These procedures are supplemented by forms, outlines, and technical
criteria to be used in implementation. It is anticipated that the indi-
vidual states will formally or informally adopt the procedures and
supplementary material, with such modifications as each may wish to
make to meet state organizational and administrative needs. It is in-
tended that the recommendations will be updated and modified as ex-
perience shows it to be necessary.
An example of the application of ORSANCO Resolution 1-73 to a parti-
cular state is provided by Warner (1972) in a report to the Illinois
Institute for Environmental Quality.
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OTHER WELLS
In addition to the types of industrial wastewater injection wells dis-
cussed above, other classes of deep wells are possible sources of
groundwater contamination. Such wells include those used in con-
junction with oil exploration and production, solution mining, geo-
thermal energy production, sewage treatment, desalination, radio-
active waste disposal, and underground gas storage.
Many of the technical and regulatory aspects that have previously been
described apply to these wells just as to industrial wastewater injec-
tion wells. The differences that exist will be discussed.
PETROLEUM INDUSTRY WELLS
Deep wells are used by the petroleum industry for exploration, for
production of oil and gas, and for injection back into the subsurface of
brines brought to the surface during oil production. The purpose of
brine injection may be to maintain reservoir pressure, to provide a
displacing agent in secondary recovery of oil, or to dispose of the brine.
The total number of petroleum exploration and production wells that
have been drilled in the United States since the first oil well was con-
structed in 1859 is unknown, but they number in the millions. Iglehart
(1972) reported, in the American Association of Petroleum Geologists
46th annual report on drilling activity in the United States, that 27, 300
wells were drilled in 1971, a year in which drilling activity was at a
low level. The number of existing brine injection wells is not docu-
mented either, but inquiry among the oil producing states indicated
that in 1965 about 20, 000 such wells existed in Texas alone (Warner,
1965), with probably an equal number distributed among all other states.
Information gathered by the Interstate Oil Compact Commission (1964)
shows that about 360 billion gallons of water were produced in 1963 in
conjunction with petroleum. At that time, about 72 percent of the pro-
duced water -was reinjected. The relative percent being reinjected
2-33
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today is undoubtedly higher, since other means of disposal, such as
unlined pits, have since been outlawed in Texas and other states.
Hazard to usable ground-water may result from any deep well, including
petroleum production wells, that are inadequately cased, cemented, or
plugged. Such wells provide avenues for interaquifer movement of
saline groundwater and other fluids. A particular danger to usable
groundwater is posed by the hundreds of thousands of oil and gas wells
that were drilled in the late 1800's and early 1900's and abandoned with
inadequate plugging. Examples of groundwater contamination caused
by abandoned, improperty-plugged oil and gas wells could probably be
found in most petroleum-producing states. Fryberger (1972), Wilmoth
(1971), and Thompson (1972) discuss cases from Arkansas, West
Virginia, and Pennsylvania, respectively.
The mechanism of possible groundwater contamination from oilfield
brine injection wells is essentially the same as was discussed for other
industrial wastewater injection wells. Since oilfield brine is a natural
water and does not normally contain chemicals that are extremely toxic
in small quantities, it may be of less concern as a pollutant from a
public health standpoint than some other industrial wastewaters. How-
ever, the very high levels of dissolved solids that are found in many
cases, and the volumes involved, present the potential for degradation
of very large amounts of usable groundwater if brine reinjection is not
properly managed (Ostroff, 1965). It is commonly believed that most
brine is returned to the same geologic horizon from which it was re-
move. The relative amount returned to the same horizon as compared
with that injected into other shallower horizons is not known, but sub-
stantial amounts are injected into aquifers that have not been depres-
sured by petroleum production. A particular example of this is injec-
tion of oilfield brines into the Glorieta Sandstone in the Oklahoma Pan-
handle and adjacent areas (Irwin and Morton, 1969). The hazard from
2-34
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this practice is from interaquifer flow of brine, or alternation of the
position of the freshwater saline-water interface.
The procedures and methods for control and regulation of brine injec-
tion are essentially the same as discussed for industrial wastewater
injection. Locating and plugging abandoned oil and gas wells is diffi-
cult and expensive. Pasini and others (1972) discuss the technology and
cost of plugging abandoned wells in the Appalachian area. The cost
ranged from $8, 600 to $14, 000 each for the four wells plugged in that
study.
A detailed investigation of the problems presented by one incident of
pollution of a freshwater aquifer by an oilfield brine was made by
Fryberger (1972). The present extent of the brine pollution is one
square mile; however, it will spread to affect 4-1/2 square miles and
will remain for over 250 years before being flushed naturally from the
aquifer. Several methods for rehabilitating the aquifer were examined;
costs ranged from $80, 000 to $7, 000, 000, and no method is economi-
cally justified at the present time.
2-35
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WELLS USED IN SOLUTION MINING
For many years, wells have been used to extract sulfur, salt, and
other minerals from the subsurface by injection of water and extrac-
tion of the minerals in solution. In many case, the residual brine
from such operations is disposed of through injection wells. A similar
type operation, widely practiced in areas where salt deposits exist, is
the construction of solution caverns for storage of liquid petroleum gas.
In this procedure, water is injected into the salt beds and a cavern
developed as the salt is dissolved and the brine pumped out. The ex-
tracted brine is then disposed of by injection into a suitable aquifer.
A relatively new but growing practice is the in-situ mining of metals,
particularly copper ; by injection through wells of acid into an ore body
or a tailings pile, then extraction of the solution containing the metal
through pumping wells or as seepage. In at least one case, a deep in-
jection well is planned for disposal of the spent acid solution, after the
metals have been removed.
The potential problems of groundwater pollution from solution mining
of soluble minerals and the techniques for prevention of such pollution
are similar to those described previously. Solution mining of metallic
minerals presents a different problem, in that the mining will, in most
cases, be in geologic strata containing usable water. Therefore, the
mining itself may need to be carefully managed to avoid groundwater
contamination. Disposal of the spent acid solutions by injection would
be similar to other industrial wastewater injection.
McKinney (1973) and Pernichele (1973) discuss current trends in solu-
tion mining and mining geohydrology and list a number of recent
references.
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GEOTHERMAL ENERGY WELLS
The Geothermal Steam Act of 1970 (Public Law 91-581) provides an
important impetus to the further development of geothermal energy
sources. In the United States, about 1. 8 million acres are designated
as known geothermal resource areas and an additional 95. 7 million
acres have prospective value (USGS, 1971). Of the known areas, 90
percent lie in the thirteen western states and Alaska. Geothermal
reservoirs may contain either dry steam or hot brines, with the latter
predominating. Both condensed steam and cooled brines commonly are
reinjected through wells into the geothermal structure (US Department
of the Interior, 1971).
At present, the two most significant geothermal areas in the United
States are The Geysers and Imperial Valley, both in California.
A substantial amount of electrical energy already is generated from
dry steam produced at The Geysers. A three-fold increase in capacity
is planned by 1975. Injection wells are used to return condensate to the
reservoir. Because of oxygen content, the condensate is reported to be
corrosive, necessitating the use of special materials (Chasteen, 1972).
The United States Bureau of Reclamation and others have proposed
major developments of geothermal energy from the hot brine reser-
voirs underlying the Imperial Valley. The Bureau of Reclamation con-
cept contemplates production of 2-. 5 million acre-feet of fresh water
per year. The 3 to 4 million a-f of brines withdrawn would be replaced
by water from the Pacific Ocean, the Salton Sea, or other sources.
Replacement water would be injected through approximately 100 wells
on the periphery of the geothermal field, to maintain reservoir pres-
sures and preclude land subsidence and lowering of the overlying fresh-
water table (Bureau of Reclamation, 1972). The high pressures and
temperatures and the corrosiveness of the injected fluid are a particu-
lar problem in such injection wells; plugging a well if subsurface casing
damage occurs could be difficult or even impossible.
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WELLS FOR INJECTION OF SEWAGE EFFLUENT
AND DESALINATION PLANT BRINES
A few wells have been constructed in Florida, Hawaii, Louisiana, and
Texas for injection of treated sewage effluent into saline water aquifers.
It has also been proposed to dispose, by injection, of brines from ad-
vanced waste treatment plants using desalination techniques and from
plants constructed to produce usable water by desalination methods.
The technology of injecting such waters is similar to that previously
discussed. The particular problem with this category of wastewaters
is the potentially very large volume that may be produced. In general,
disposal of sewage effluent by injection into saline aquifers probably
is not desirable for at least two reasons: the effluent is of too high a
quality to waste, and the amount that can be safely injected is too
small to be significant in solving the overall problem of managing such
wastes.
Injection of brines from desalination plants may be the most desirable
method of disposing of these wastes in cases where the geology is
suitable and the volumes of waste are not too large. (Dow Chemical
Company, 1972.)
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RADIOACTIVE WASTE DISPOSAL WELLS
The possible use of injection wells for disposal of radioactive wastes
has been the subject of extensive investigation since the early 1950's.
To date, at least three wells have been constructed for injection of
liquid radioactive wastewaters into deep aquifers, but the only one
that has been operated is located at a uranium mill at Grants, New
Mexico (Arlin, 1962). In spite of the limited use of injection wells in
the past, they may be the most desirable means of handling some
radioactive liquids today and perhaps others in the future (de Laguna,
1968; Belter, 1972).
Particular problems related to injection of liquid radioactive waste
are the possible extreme toxicity of the waste and heat generation
from radioactive decay in the subsurface.
A second method of radioactive waste disposal through wells is injec-
tion of radioactive wastes incorporated in cement slurries into hydraulic
fractures induced in thick shale beds. This method of disposal has been
used for intermediate level wastes at the Oak Ridge National Laboratory
since 1966 and is being tested at the Nuclear Fuel Services Chemical
Processing Plant site in West Valley, New York (Belter, 1972). A
discussion of the environmental aspects of this disposal method is pro-
vided by de Laguna and others (1971).
2-39
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GAS STORAGE WELLS
Underground gas storage may be defined as storage in rock of synthetic
gas or of natural gas not native to the location. Storage can be in de-
pleted oil or gas reservoirs, in groundwater aquifers, in mined caverns
or in dissolved salt caverns. Gas may be stored in gaseous or liquid
form.
The largest quantities of gas are stored in the gaseous form in depleted
oil or gas reservoirs or in groundwater aquifers. In 1971 there were
333 underground gas storage fields in 26 states. About 60 percent of
the storage capacity was located in Illinois, Pennsylvania, Michigan,
Ohio, and "West Virginia. The number of wells per field ranges from
less than 1 0 to more than 100, depending on the size of the structure
in which the gas is being stored. (American Gas Association, 1967
and 1971.)
Underground gas storage fields present a potential for contamination
of usable groundwater by upward leakage of gas through the cap rock,
through abandoned improperly plugged wells, or through inadequately
constructed gas injection or withdrawal wells. Gas could also escape
from an overfilled field and migrate laterally in the storage aquifer,
which in some cases contains usable water. A case history of a leaky
storage field in Illinois was documented by Hallden (1961). In that
instance, it was not possible to conclusively determine whether the
leakage was from faulty well cementing, lack of an adequate cap rock,
faulting of the cap rock, or unplugged abandoned wells. Some leakage
from storage fields is common; but, since the gas is a valuable com-
modity, operating companies have a strong interest in minimizing
such losses. In addition, storage fields are subject to state or federal
licensing and regulation, the engineering characteristics of a field must
be carefully determined prior to licensing, and the fields must be
monitored during operation.
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References
1. American Gas Association, Inc., Survey of Gas Storage Facilities
in United States and Canada, New York (1967).
2. American Gas Association, Inc. , The Underground Storage of
Gas in the United States, New York (1971).
3. Arlin, Z. E. , "Deep-Well Disposal of Uranium Tailing Water, "
Proceedings 2nd Conference on Ground Disposal of Radioactive
Wastes, Chalk River, Canada, US Atomic Energy Commission
TID-7628, Bk. 2, pp 356-360 (1962).
4. Ballentine, R. K. , Reznek, S. R. , and Hall, C.W., Subsurface
Pollution Problems in the United States, US Environmental Pro-
tection Agency Technical Studies Report TS-00-72-02,
Washington, D. C. (1972).
5. Belter, W. G. , "Deep Disposal Systems for Radioactive Wastes, "
Underground Waste Management and Environmental Implications,
American Association of Petroleum Geologists Memoir 18, Tulsa,
Oklahoma (1972).
6. Bureau of Reclamation, Geothermal Resource Investigations,
Imperial Valley, California; Developmental Concepts, US Depart-
ment of the Interior, Boulder City, Nevada, 58 pp (1972).
7. Chasteen, A. J. , "Geothermal Energy — Growth Spurred on by
'Powerful Motives', " Mining Engineering, Society of Mining
Engineers of AIME, Vol. 24, No. 10, pp 100-102 (1972).
8. Cook. T. D. (editor), Underground Waste Management and
Environmental Implications, American Association of Petroleum
Geologists Memoir 18, Tulsa, Oklahoma, 412 pp (1972).
9. de Laguna, W. , "Importance of Deep Permeable Disposal
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Strata, American Association of Petroleum Geologists Memoir
10, pp 21-31 (1968).
10. de Laguna, W. , et al, Safety Analysis of Waste Disposal by
Hydraulic Fracturing at Oak Ridge, Oak Ridge National Labora-
tory Report 4665, Oak Ridge, Tennessee, pp 1-6 (1971).
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11. Donaldson, E.G., Subsurface Disposal of Industrial Wastes in
the United States, US Bureau of Mines Information Circular 8212,
34 pp (1964).
12. Dow Chemical Company (Freeport, Texas), "Final Disposal of
Effluent Brines from Inland Desalting Plants, " Environment
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13. Ferris, J. G., "Response of Hydrologic Systems to Waste
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14. Dryberger, J. S. , Rehabilitation of a Brine-Polluted Aquifer,
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15. Galley, J. E. (editor), Subsurface Disposal in Geologic Basins,
American Association of Petroleum Geologists Memoir 10, Tulsa,
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16. Galley, J. E. , "Geologic Basin Studies as Related to Deep-Well
Disposal, " Proceedings 2nd Conference on Ground Disposal of
Radioactive Wastes, Chalk River, Canada, US Atomic Energy
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17. Goolsby, D. A. , "Hydrogeochemical Effects of Injecting Wastes
Into a Limestone Aquifer Near Pensacola, Florida, " Ground
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Education and Welfare, R. A. Taft Sanitary Engineering Center,
Technical Report W61-5, Cincinnati, Ohio, 218 pp (1961).
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Bulletin, American Association of Petroleum Geologists, Vol. 56,
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21. Interstate Oil Compact Commission, Water Problems Associated
with Oil Production in the United States, Oklahoma City, Okla-
homa, 88 pp (1964).
22. Irwin, J. H. , and Morton, R. B. , Hydrogeologic Information on
the Glorieta Sandstone and the Ogallala Formation in the Okla-
homa Panhandle and Adjoining Areas as Related to Underground
Waste Disposal, US Geological Survey Circular 630, 26 pp (1969).
23. Ives, R. E. , and Eddy, G. E. , Subsurface Disposal of Industrial
Wastes, Interstate Oil Compact Commission, Oklahoma City,
Oklahoma, 109 pp (1968).
24. Love, J. D. , and Hoover, L. , A Summary of the Geology of
Sedimentary Basins of the United States, with Reference to the
Disposal of Radioactive Wastes, US Geological Survey Trace
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25. McKinney, W. A. , "Solution Mining, " Mining Engineering, pp 56-
57, February (1973).
26. Ostroff, A. G. , Introduction to Oilfield Water Technology,
Prentice-Hall, Inc. , Englewood Cliffs, New Jersey, 412 pp
(1965).
27. Pasini, J. , III, et al, "Plugging Abandoned Gas and Oil Wells, "
Mining Congress Journal, pp 37-42, December (1972).
28. Pernichele, A. D. , "Geohydrology, " Mining Engineering, pp 67-
68, February (1973).
29. Rima, R. , et al, Subsurface Waste Disposal by Means of Wells —
A Selective Annotated Bibliography, US Geological Survey Water -
Supply Paper 2020 (1971).
30. Roedder, E. , Problems in the Disposal of Acid Aluminum
Nitrate High-Level Radioactive Waste Solutions by Injection Into
Deeplying Permeable Formations, US Geological Survey Bulletin
1088, 65 pp (1959).
31. Selm, R. P. , and Hulse, B. T. , "Deep-Well Disposal of Industrial
Wastes, " 14th Industrial Waste Conference Proceedings, Purdue
University Engineering Extension Series No. 104, pp 566-586
(1959).
2-43
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32. US Department of the Interior, Geothermal Leasing Program,
NTIS Accession No. PB 203 102-D, Washington, D. C.
(1971).
33. US Environmental Protection Agency, Subsurface Water Pollution,
A Selective Annotated Bibliography, Part 1, Subsurface Waste
Injection, Office of Water Programs, Washington, D. C. , 156 pp
(1972).
34. Van Everdingen, A. F. , "Fluid Mechanics of Deep-Well
Disposals, " Subsurface Disposal in Geologic Basins - A Study of
Reservoir Strata, American Association of Petroleum Geologists
Memoir 10, Tulsa, Oklahoma, pp 32-42 (1968).
35. Warner, D. L. , Deep-Well Injection of Liquid Waste, US Public
Health Service Environmental Health Service Publication No.
999-WP-21, 55 pp (1965).
36. Warner, D. L. , "Deep-Well Waste Injection — Reaction with
Aquifer Water, " Proceedings, American Society of Civil Engi-
neers, Vol. 92, No. SA4, pp 45-69 (1966).
37. Warner, D. L. , Deep-Wells for Industrial Waste Injection in the
United States — Summary of Data, Federal Water Pollution Con-
trol Administration, Water Pollution Control Research Service
Publication No. WP-20-10, 45 pp (1967).
38. Warner, D. L. , "Subsurface Disposal of Liquid Industrial Wastes
by Deep-Well Injection, " Subsurface Disposal in Geologic Basins —
A Study of Reservoir Strata, American Association of Petroleum
Geologists Memoir 10, Tulsa, Oklahoma, pp 11-20 (1968).
39. Warner, D. L. , Subsurface Industrial Wastewater Injection in
Illinois, Illinois Institute for Environmental Quality Document
No. 72-2, 125 pp (1972).
40. Warner, D. L. , Survey of Industrial Waste Injection Wells. 3
Vols. , Final Report, US Geological Survey Contract No. 14-08-
0001-12280, University of Missouri, Rolla, Missouri (1972).
41. Wilmoth, B. M. , "Occurrence of Salty Groundwater and Meteoric
Flushing of Contaminated Aquifers, " Proceedings of National
Groundwater Quality Symposium, EPA Water Pollution Control
Research Series 16060 GRB 08/71 (1971).
42. Young, A. , and Galley, J. E. (editors), Fluids in Subsurface
Environments, American Association of Petroleum Geologists
Memoir 4, Tulsa, Oklahoma, 414 pp (1965).
2-44
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INJECTION WELLS INTO FRESHWATER AQUIFERS
Scope of the Problem
Although most of the estimated 15 million wells in the United States are
used for the production of fresh water, many thousands of wells in various
parts of the country have been and are still being used only for disposal
of pollutants into freshwater aquifers. This practice has been followed,
for example, by the petroleum industry in some areas for getting rid of
brines and by other industries for disposing of chemical wastes. Fuhriman
and Barton (1971), referring to groundwater pollution in the southwestern
United States, state that "occasionally, industries or others have used
shallow injection wells to dispose of liquid wastes, " and cite as an example
electronic industries that disposed of metalplating wastes by means of
injection wells in Arizona.
In parts of Florida and Ohio, wells tapping limestone aquifers have been
used to dispose of domestic sewage from individual homes. Similarly, in
Oregon (Sceva, 1968; Oregon State Sanitary Authority, 1967) domestic
sewage effluent is discharged from septic tanks into deep rock wells
drilled into basalt aquifers (Figure 2-3). For the past several decades,
thousands of wells in New York, in California, and in several midwestern
states have been used to inject heated water from cooling systems into
freshwater aquifers.
In the Snake River Plain of Idaho, wells are -widely used to dispose of
wastes into the underlying permeable basalt aquifer. A recent inventory
in the area indicates that there are approximately 1500 wells for disposal
of surface runoff and waste irrigation, perhaps ZOOO wells for disposal
of sewage, and additional wells for street drainage and industrial use.
At the National Reactor Testing Station, low-level aqueous radioactive
wastes have been discharged into the same basalt aquifer through a drilled
well since 1953 (Jones, 1961).
2-45
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Land Surface
Disposal Well
Septic Tank
^r-Surface Casing
. Basalt
- Roclc
rv - i
.
'
^
"*
-
X
I
\
1
/
> X
/ '
X
•Sv .
'
-------
In recent years, as pressure on municipalities to abate pollution of
surface waters has increased, greater attention has been given to the
possibility of injecting treated municipal sewage into wells penetrating
freshwater aquifers. Several of the proposed schemes not only would
solve a sewage-disposal problem but also would help to recharge fresh-
water aquifers or to establish hydraulic barriers against saltwater
encroachment in freshwater aquifers. Advanced pilot experiments are
being conducted along these lines in Long Island (Vecchioli and Ku, 1972)
and in California (Baier and Wesner, 1971). The procedure is relatively
costly because the sewage must be given at least secondary treatment
and preferably tertiary treatment in order to prevent clogging of the
injection wells and to reduce or prevent significant chemical and bacteri-
ological contamination of the aquifer.
Modification of the existing quality of the native groundwater caused by
subsurface disposal of wastes through a well depends on a variety of
factors, including the composition of the native water, the amount and
composition of the injected waste fluid, the rate at which the injection
takes place, the permeability of the aquifer, the type of construction and
life expectancy of the well, and the kinds of biological and chemical
degradation that may take place within the well and the aquifer. In gen-
eral, for economic reasons, wells used for disposal of contaminated
liquids in freshwater aquifers tap the shallowest available aquifer.
Commonly, this is a water-table aquifer. Some disposal wells, however,
are terminated at greater depths in confined freshwater aquifers.
Environmental Consequences
Initially, injection of contaminated liquids through wells into freshwater
aquifers causes degradation of the chemical and bacteriological quality
of the groundwater in the immediate vicinity of the injection facilities.
Eventually, the degradation spreads over a wider region and may
2-47
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ultimately extend into surface waters that are hydraulically connected
with the receiving aquifer. If the water-level cones of depression around
nearby operating water-supply wells are large enough to include the
injection site, or if the wells are down-gradient along natural flow lines
from the injection site, contamination of these wells may take place.
Another potential effect in some hydrogeologic environments is move-
ment of the contaminated water from the injection zone into overlying or
underlying freshwater aquifers.
Nature of Pollutants
The principal kinds of contaminated fluids that are intentionally injected
through wells into freshwater aquifers, other than those from agricultural
and mining wastes, are cooling water, sewage, stormwater, and indus-
trial wastes.
In the case of cooling water returned to the same aquifer from which it
has been pumped, the chemical quality of the water is usually unchanged
from that of the native water except for an increase in temperature.
Increased solubility of aquifer materials due to a rise in temperature is
believed to be insignificant, except perhaps in carbonate aquifers. How-
ever, in some instances, sequestering agents such as complex polyphos-
phate-based chemicals added to the water to inhibit oxidation of iron may
become a source of pollution to an aquifer.
Domestic sewage being disposed of into individual household wells is a
highly polluted •waste with organic and inorganic substances, bacteria,
and viruses. It may receive little natural treatment during passage
through septic tanks and cesspools except for settling of the solids, some
biochemical degradation of the wastes, and filtration of part of the large
bacterial population. On the other hand, the quality of the municipal
sewage effluent released for disposal into wells depends on the degree of
treatment before disposal and the source of the sewage. Municipal
2-48
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sewage generally consists mainly of domestic wastes with a high
content of dissolved solids, including nitrogen-cycle constituents, phos-
phate, sulfate, chloride, and detergents (methylene-bloc active sub-
stances, or MBAS). In some localities municipal sewage contains sub-
stantial amounts of industrial wastes. Different degrees of treatment
may remove or reduce the concentrations of certain constituents, but
even with the most advanced forms of sewage treatment many dissolved
constituents including heavy metals remain in the •wastes.
The chemical qualities of tertiary treated sewage, native groundwater,
and water recovered from observation wells, from an experimental
injection study in Long Island, New York, are shown in Table 2-12. The
concentrations of ammonia, iron, phosphate, sulfate, and other con-
stituents as well as the dissolved solids content were significantly higher
than those of the native groundwater. No analyses of the treated waste
were made for heavy metals or other objectionable constituents. The
bacterial count in the treated sewage was low due to heavy chlorination
before injection.
Stormwater runoff generally has a low dissolved-solids content. How-
ever, the initial slug of stormwater may be contaminated with animal
excrement, traces of pesticides, fertilizer nitrate from lawns, organics
from combustion of petroleum products, rubber from tires, bacteria,
viruses, and other miscellaneous contaminants. Where deicing salts
are applied to roads in the winter, the chloride content of the stormwater
may rise temporarily to several thousand mg/-t-.
Industrial wastes injected through wells range widely in composition and
toxicity, depending on the particular industrial operation and the degree
of treatment of the wastes before disposal. Plating wastes, pickling
wastes, acids, and other toxic materials are some of the more common
fluids disposed of through wells into freshwater aquifers.
2-49
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Table 2-12. Selected chemical-quality characteristics of native water and
tertiary treated injection water (after Vecchiolo and Ku, 1972).
Tertiary Treated
Constituent Injection Water
(mg/l)
Total iron
Free CO2
Fluoride
Ammonia nitrogen
Albuminoid nitrogen
Nitrite nitrogen
Nitrate nitrogen
Oxygen consumed
Chloride
Total hardness
Total alkalinity
PH
Total solids
MBAS
Calcium hardness
Total phosphate
Orthophosphate
Sulfate
Silica
Calcium
Magnesium
Sodium
Potassium
0.24
21
.26
25
.36
. 00
<. 05
3
73
72
77
7.0
357
. 02
42
3.6
3. 1
137
14
18
5.2
69
11
Contaminated Water Recovered from
Native Groundwater Observation Wells
Depth 560 ft.
(mg/t)
0.6
-
. 01
-
-
-
.00
-
3.7
-
-
5. 6
23
-
-
. 01
-
4. 1
7.4
.34
. 17
3.7
.60
Depth 480 ft. ;
Distance 20 ft.
(mK/l)
0. 91
105
.23
18. 5
.24
<.001
<.05
2
74
42
33
5.8
321
<.02
22
.60
.50
138
10
8.2
4.2
67
9
Depth 460 ft. ;
Distance 100 ft.
(mg/-t)
1. 30
100
<. 10
1.38
.04
<. 001
<. 05
1
24
34
6
5. 1
123
<.02
16
.02
<.01
54
8.0
7.2
3.3
22
1.6
-------
Pollution Movement
In principle, any well that produces -water -will also accept water. The
rate of acceptance is dependent on the nature of the injected fluid, the
hydraulic properties of the aquifer, and other factors. In some wells
penetrating very permeable aquifers, water can be introduced under
gravity conditions at rates that may be as high as several hundred gallons
per minute or more without causing overflows. In contrast, a well pene-
trating a very poor aquifer may accept only a fraction of a gallon per
minute by gravity flow. If pumps are installed so that the fluid is injected
under pressure, the rate of injection can be substantially increased.
The rate of injection is governed by the permeability and thickness of the
aquifer,, the depth to the natural water level in the well, the diameter of
the well, the area of openings in the well screen, and the chemical com-
patability of the injected fluid -with the native groundwater. If the fluid
being injected contains suspended material or air bubbles, for instance,
rapid clogging of the aquifer can occur so that the injection rate falls off
sharply. Growth of certain kinds of bacteria and formation of chemical
precipitates within the well and the adjacent aquifer also can interfere
with injection. In the case of a water-table aquifer, a further limitation
on the rate of injection is that the induced rise of the groundwater level
may cause breakthrough and overflow at the land surface.
Injection of fluid through a well creates a local groundwater mound in an
unconfined aquifer and a pressure mound in a confined aquifer. These
mounds are essentially mirror images of the water-level cones of depres-
sion that develop around pumping wells tapping the same types of aquifers.
The configuration of a particular mound is generally symmetrical, -with
the maximum rise in water level being observed at the well. Hypothetical
shapes of contaminated water bodies in homogeneous unconfined and con-
fined aquifers are shown in Figure 2-4. Departures from these shapes
2-51
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WELL
Liquid contaminants
0 °V ,' » 0 •$ .°.'j I'o'o.'o 0 -0 '„' a
• >.%-., =.Vo ».°;.Yo">.-,°
•• ,.«•.•.. ».o... «;«.°. °-°
3 0 0 • - i"» O «. 0 . , ',«•-. o .» . V
> j.' • «-o«.«' o-..oo.
I0°.«oi>0,«o.0«ofl0<'»eo " C'"*
."oooOr- "«°o o' ' • "."-"oo*1
^S, • • * New water table o . ••„ 0 „ .• ° ,
"' ' ° '' •
lj*"*V,*o ,»<•?.» * ^ ' ' • ' Old w"er table
fesfi^^ii
_— Aquiclude .
A. Water table aquifer
WtLL ~~ Liquid contaminants
- Aquiclude
^— .New piezometric surface- •
^_^ —^fc ^^ ^^ I !..• - - — ^^^ ^^~~ ^^
— Original -=—*
- gradient
1 o Aquifer •
o * * " -c "***rV**'*^:*t'**4tw4j
'••'oj o', » • o .'* *Vtj^*»*ji«'.y
- — Aquiclude -
B. Artesian aquifer
Figure 2-4. Hypothetical pattern of flow of
contaminated water (shaded)
injected through wells into water
table and artesian aquifers
(after Deutsch, 1963).
2-52
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may develop where aquifer lithologies are non-uniform and where the
natural groundwater flow is significant.
After it has entered the saturated zone, the injected fluid begins to move
radially away from the well, displacing the native groundwater in its path
and creating a zone of mixed water along the perimeter of the contami-
nated body. The polluted water moves slowly in the direction of the
hydraulic gradient toward a point of discharge, which may be a well, a
spring, or a surface water body. Where injection wells leak due to
corrosion, casing breaks, or poor construction, the contaminated water
may move into freshwater aquifers above or below the injection zone.
Examples of the Use of Injection Wells
Since 1965, a pilot experiment on recharging tertiary-treated sewage in
order to create a hydraulic barrier against saltwater encroachment has
been conducted by the U. S. Geological Survey in cooperation with the
Nassau County Department of Public Works at Bay Park, Long Island
(Vecchioli and Ku, 1972). There, a specially constructed injection well
(Cohen and Durfor, 1966), 480 feet deep, with a fiberglass casing, stain-
less steel screen, and auxiliary monitoring wells at depths ranging from
about 100 to 700 feet, were installed to investigate the hydraulic and
geochemical problems associated -with the injection of treated sewage
into a confined aquifer used for public -water supply. The injected water
moves radially from the well as a thin body in the injection zone, and
has been detected by monitoring wells as much as 200 feet away.
As shown in Table 2-12, significantly higher concentrations of iron,
ammonia, sulfate, chloride, sodium, and other dissolved constituents
were present in the water at distances of 20 feet and 100 feet than in the
native groundwater. Bacteria were apparently filtered out after about
20 feet of travel. The experimental results indicated that even low
turbidity of the effluent and bacterial growth around the well screen can
cause clogging and excessive head buildup in the injection well.
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Similar experiments in California on recharging freshwater aquifers with
Colorado River water and with reclaimed sewage (McGauhey and Krone,
1954), mainly as a barrier against seawater encroachment, have been
successfully conducted. Some barrier systems using highly treated river
water are operational. Baier and Wesner (1971) have described experi-
ments by Orange County Water District in which tertiary-treated effluent
from a trickling filter sewage plants -was injected into unconsolidated
aquifers at depths of about 100 to 350 feet. The experiments indicated
that after about 500 feet of travel, the injected water was free of viruses,
bacteria, and toxic substances, and the ammonia content was substantially
reduced. However, the hardness and alkalinity of the water increased,
the water had a musty odor and taste, and the dissolved solids content
exceeded 1, 000 mg/-t. Additional pre-treatment of the reclaimed waste
water will improve the quality of the water intended for injection, and
the dissolved-solids content will be reduced to drinking water standards
by mixing reclaimed waste water with desalted sea water before injection.
Since the early 1930's, the State of New York has required that water
pumped from wells on Long Island at rates of 45 gpm or more must be
returned, through a closed system of specially constructed recharge
wells, into the same aquifer from which the water was pumped. This
requirement was imposed because heavy pumping had caused a sharp
decline in groundwater levels in western Long Island, with coastal en-
croachment of sea water. The heated effluent returned to the ground,
which may range from 10 to 30°F warmer than the natural groundwater,
has increased the local temperature of shallow aquifers (Leggette and
Brashears, 1938). Warming of the groundwater, although of concern to
users of groundwater for cooling, has been regarded as less detrimental
than the saltwater encroachment that could result from declining ground-
water levels.
2-54
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In parts of western Long Island, stormwater that collects at street inter-
sections subject to flooding is disposed of into dry wells that act as drains.
The wells are lined with large-diameter pre-cast perforated concrete
rings. The stormwater moves downward through the wells into a shallow
aquifer. Hundreds of dry wells are also used for highway drainage in
other parts of the country; notable are those in the Fresno area of
California (Gong-Guy, in Schiff, 1963). In a few places, wells also have
been drilled within ponds to drain them. Drainage wells commonly provde
a short path for potential vertical movement of inorganic and organic
contaminants and bacteria into an underlying aquifer.
Control Methods
Where injection of wastes through wells into freshwater aquifers is pro-
posed or is in progress, a hydrogeological investigation should be under-
taken as a first measure to control potential groundwater pollution. This
should include:
1. Definition of the hydrogeologic environment and the factors
affecting the groundwater flow.
2. Existing or planned nearby wells should be located.
3. The directions and rate of movement of the potential contami-
nated fluid should be ascertained, so that estimates can be
made of how much time will elapse before the arrival of the
contaminated water at nearby wells.
4. Studies should be undertaken to determine the possibility of
inter- and intra-aquifer movement of the injected water.
5. Information should be compiled on the chemical, biological,
and physical properties of the waste fluids; the degree of
pre-treatment needed; and the compatibility of the treated
fluids with the native groundwater.
2-55
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6. An evaluation should be made of the most suitable locations
and spacings of injection wells and of the rate of injection.
7. Consideration should also be given to the future land use of
the injection-well sites.
Where the threat from contaminated groundwater is severe, steps may
have to be taken to block the underground flow of the waste fluids or to
actually remove the fluids by pumping. Blocking of the movement of the
contaminant can be accomplished by constructing physical subsurface
barriers, although this is not an economically feasible solution in most
hydrogeologic environments. Diverting the flow by creating a hydraulic
barrier is another approach that may be implemented in many places.
This can be accomplished by injecting fresh water through wells installed
across the path of flow or by pumping from wells so as to induce the
contaminants to flow toward these •wells.
Pumping polluted fluids back out of the ground may create a new pollution
problem where the wastes are pumped into surface water. However, if
facilities can be provided for proper treatment and disposal of the pumped
water, pumping from wells can be a practicable solution.
Alternatives to disposing of wastes through injection should, of course,
be examined. A careful evaluation of alternatives is required, to avoid
adopting an expedient that may prove to have other and perhaps more
harmful effects. Sewering, for example, which exports the waste, can
have deleterious effects due to loss of recharge and consequent lowering
of water levels and possibly saltwater intrusion. In the case of cooling
water being returned to the aquifer from -which it is drawn, an alternative
is to use atmospheric heat exchangers instead of the cooling water. Here,
the loss of efficiency of the cooling system must be considered; more
electrical energy may be required, with attendent air and thermal
2-56
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pollution problems. Also, the undesirable "heat island" effect noted
in large cities would be further increased by widespread use of atmo-
spheric heat exchangers in place of the groundwater for cooling.
Halting the disposal of wastes into wells may be highly desirable, but it
should be noted that halting the injection represents only a partial pollu-
tion control measure; fluids already injected will continue to pollute the
aquifer.
Monitoring Procedures
After a clear understanding has been developed of the hydrogeologic
environment and of the mechanisms of contamination, a monitoring
system should be designed and implemented to provide continuing sur-
veillance of polluted water and of the efficiency of any control measures
that may be instituted. Depending on local conditions, it may be neces-
sary to construct a series of wells at different depths in the polluted
aquifer and at scattered nearby locations. Periodic monitoring of these
wells for chemical content of the groundwater and changes of groundwater
levels can provide valuable data on the behavior of the underground con-
tamination and on the environmental threats to water wells or to other
freshwater resources in the vicinity.
2-57
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References
1. Baier, B.C., and Wesner, G. M. , "Reclaimed Waste Water for
Ground-Water Recharge, " Jour. American Water Resources
Assoc., v. 7, no. 5, pp. 991-1001 (1971).
2. Cohen, Philip, and Durfor, C. N. , "Design and Construction of a
Unique Injection Well on Long Island, New York, " Geological
Survey Research, 1966, U. S. Geol. Survey Prof. Paper 550-D,
pp. D253-D257 (1966).
3. Deutsch, Morris, Ground-Water Contamination and Legal Controls
in Michigan, U. S. Geol. Survey Water-Supply Paper 1691, 79 pp.
(1963).
4. Fuhriman, D. K. , and Barton, J. R. , Ground Water Pollution in
Arizona, California, Nevada, and Utah, U. S. Environmental
Protection Agency, Water Pollution Control Research Series 16060,
249 pp. (1971).
5. Jones, P. H. , Hydrology of Waste Disposal National Reactor Testing
Station, Idaho, U. S. Geol. Survey Interim Report for U. S. Atomic
Energy Comm. , Idaho Falls, Idaho (1961).
6. Leggette, R. M. and Brashears, M. L. , Jr., "Ground Water for Air
Conditioning on Long Island, New York, " Trans. Amer. Geophys.
Union, pp. 412-418 (1938).
7. McGauhey, P. H. , and Krone, P. B. , Report on the Investigation of
Travel of Pollution, California State Water Pollution Control Board,
Publ. no. 5, 218 pp. (1954).
8. Oregon State Sanitary Authority, Water Quality Control in Oregon,
Oregon State Sanitary Authority, vol. 1, 113pp. (1967).
9. Sceva, J. E. , Liquid Waste Disposal in the Lava Terranes of Central
Oregon, U. S. Federal Water Pollution Control Admin. , Northwest
Region, Pacific Northwest Water Laboratory, Corvallis, Oregon
(1968).
10. Schiff, Leonard, (Editor), Ground Water Recharge and Ground
Water Basin Management, Proc. 1963 Biennial Conference Ground
Water Recharge Center, Fresno, Calif. (1963).
2-58
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11. Vecchioli, John, and Ku, F. H. , Preliminary Results of Injecting
Highly Treated Sewage Plant Effluent into a Deep Sand Aquifer at
Bay Park, New York, U. S. Geol. Survey Prof. Paper 751A,
14pp. (1972).
2-59
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LAGOONS, BASINS, PITS
Use of Lagoons, Basins, and Pits
In general, a lagoon comprises a natural depression in the land or a
sector of some bay, estuary, or wetland area diked off from the
remainder. No sharp line of definition distinguishes it from a basin,
which is most commonly constructed by formal diking or by a combina-
tion of excavating and diking. Pits are distinguished by a small ratio
of surface area to depth.
Unlike excavations used in septic systems or in landfill operations,
lagoons, basins, and pits are usually open to the atmosphere, although
pits and small basins may sometimes be placed under roof. Some are
intended to discharge liquid to the soil system and hence to the ground-
water, others are designed to be watertight. The former are, there-
fore, unlined structures sited on good infiltrative surfaces; the latter
are lined •with puddled clay, concrete, asphalt, metal, or plastic
sheeting. Thus, both by design and by accident or failure, this type of
structure is of concern in the context of groundwater quality.
Lagoons and basins are adapted to a wide spectrum of municipal and
industrial uses including storage, processing, or waste treatment on a
large scale. For example, the unlined lagoon or basin may serve as a
large septic tank for raw sewage, a secondary or tertiary sewage oxi-
dation pond, or as a spreading basin for disposing of effluent from
treatment ponds or conventional wastewater treatment plants by ground-
water recharge. In industry the unlined system may serve as a cooling
pond or to hold hot wastewater until its temperature is suitable for dis-
charge to surface waters, or to store wastewater for later discharge
into streams during flood flows or for application to the land during the
growing season. Some unlined lagoons are used for a special purpose
such as evaporating ponds to concentrate and recover salt from saline
water.
2-60
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Lined basins are used for a number of purposes, including evaporation
ponds for concentrating salts or process brines. Recovery of minerals,
or more economic disposal of the concentrate, may be the motivating
factor. In oil fields, refineries, and chemical processing plants are
used as holding sumps for brines or wastes as a stage in disposal by
deep well injection or other acceptable procedure. In the East Bay area
of California, a lined basin has served as a receiving sump for fruit
and vegetable cannery wastes to be barged to sea or hauled to land
disposal sites.
Unlined pits serve to a limited extent in sewerage; examples include pit
privies and cesspools or percolation devices in septic systems. They
are also widely used to dispose of storm water from roof drains. In
California both pits and basins are used to dispose of storm water which
would otherwise collect in highway underpasses and interfere with
traffic.
Lined pits have historically been used in industry for processes ranging
from tanning of animal hides to metal plating. They are commonly used
to house sewage pumps below the ground level. In both industry and
municipal sewerage they are used as intake sumps in pumping installa-
tions. Although lined pits are commonly concrete or metal structures,
undetected leakage of highly concentrated pollutants can have a signifi-
cant local effect on groundwater.
Scope of Problem
Data by which to evaluate the existing scope of the problem of municipal
and industrial waste lagoons and similar open excavations in relation to
groundwater quality have not been assembled and analyzed. State health
departments and water quality control boards can cite instances in which
ponded contaminants have created a local pollution problem. To assess
the degree to which the use of lagoons, basins, and pits in fact degrade
2-61
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ground-water quality will require an extensive survey of the literature
and of the practice of ponding wastes and process materials. The
present outlook is that the need for such an assessment will become
increasingly great with time. Two factors support this conclusion:
• As institutionalized in the National Clean Water Act, there
is a growing reluctance of regulatory agencies to permit
waste discharges to surface waters, thus requiring either
land disposal of sewage effluents or the creation of an
increasing volume of process brines in achieving an
acceptable effluent quality.
• A growing tendency to require industry to process its own
wastes prior to discharge to the municipal sewer, thus
creating more need to use lagoons and basins either for
waste processing or for managing waste processing
brines.
Both of these developments suggest a need to control the pathways by
which contaminants may move from ponds to groundwater and to
monitor the effectiveness of control measures.
Potential Hazard to Ground-water
The potential of sewage lagoons to degrade groundwater quality is
essentially the same as that of septic systems. An extensive survey cf
the literature (McGauhey and Krone, 1967) shows that a continuously
inundated soil soon clogs to the extent that the infiltration rate is
reduced below the minimum for an acceptable infiltration system. If
the groundwater surface is too close to the lagoon bottom, a hanging
column of water will be supported by surface tension and the soil will
not drain. Clogging will then continue indefinitely even though no new
liquid is added to the system. A spreading pond designed to discharge
effluent to the groundwater must, therefore, be loaded and rested
2-62
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intermittently to maintain an acceptable recharge rate (California Water
Pollution Control Board, 1953; McGauhey and Winneberger, 1964;
McGauhey and Krone, 1967). If, however, isolating the contents of the
lagoon from the groundwater is the objective of the system, a low infil-
tration rate may still mean an undesirable quantity of polluted water
passing the water-soil interface. The pollutants carried downward with
percolating water from a sewage lagoon are those described in the sec-
tion on septic tanks. Not all of the salts introduced to the groundwater
originate in domestic use. In some instances, such as that of Colorado
River water delivered to Southern California, the mineral content of the
imported •water may be higher than that of the local groundwater.
Lagoons and pits used to recharge groundwater with runoff from
highways and roofs have little potential to affect groundwater adversely.
The tendency is to concentrate runoff at low points; however, the effect
of this concentration on the groundwater basin is minimal. Oils from
the road surface are the principal factor added to rain water in this
situation. Lead has been found to be significantly higher on the soils
along highways, but its possible movement to groundwater has not been
reported.
Liquids percolating from lagoons or basins used by industry have a
greater potential to degrade groundwater than does domestic sewage.
Chromates, gasoline, phenols, picric acid, and miscellaneous chemi-
cals have been observed to travel long distances with percolating
groundwater (Anon., 1947; Davids and Lieber, 1951; Harmon, 1941;
Lang, 1932; Lang and Gruns, 1940; McGauhey and Krone, 1967; Muller,
1952; Sayre and Stringfield, 1948). Unlined lagoons, basins, and pits
are commonly used by industry for the storage of liquid raw materials
and waste effluent. Most of these facilities are simply open excavations
or diked depressions in which the liquid is temporarily or permanently
stored. Few have been designed with proper consideration to water
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tightness, so that leakage of potential contaminants into the underlying
groundwater reservoir is very common even though the leakage may
seldom be known to exist. Liquids stored in industrial lagoons, basins,
and pits may contain brines, arsenic compounds, heavy metals, acids,
gasoline products, phenols, radioactive substances, and many other
miscellaneous chemicals (Anon., 1947; Harmon, 1941; Lang, 1932;
Lang and Gruns, 1940; McGauhey and Krone, 1967, Muller, 1952;
Perlmutter and Lieber, 1970, Sayre and Stringfield, 1948).
Where these storage areas have been actively used for many years and
leakage through the sides and bottom of a particular lagoon or basin
has taken place, the quantity of contaminated groundwater can be signi-
ficant and the plume of polluted liquid may have traveled long distances
with the percolating groundwater. In some instances, the first realiza-
tion that extensive groundwater pollution has occurred may come when
the plume reaches a natural discharge area at a stream and contamina-
tion of surface waters is noted.
An example of the fate and environmental consequences of a leaky basin
containing metal-plating waste effluent from an industrial plant is given
in Perlmutter and Lieber (1970). Plating wastes containing cadmium
and hexavalent chromium seeped down from disposal basins into the
upper glacial aquifer of southeastern Nassau County, New York. The
seepage formed a plume of contaminated water over 4, 000 feet long,
about 1, 000 feet wide, and as much as 70 feet thick. Some of the con-
taminated groundwater is being discharged naturally into a small creek
that drains the aquifer. The maximum observed concentration of hexa-
valent chromium in the groundwater was about 40 nag/I, and concentra-
tions of cadmium have been observed as high as 10 mg/1.
In another case in New Jersey, unlined waste lagoons constructed in
sand and gravel beds leaked over 20 million gallons of effluent into the
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upper 20 feet of aquifer over a period of only a few years. The
contaminated groundwater contains high concentrations of phenols,
chromium, zinc, and nickel (Geraghty & Miller, Inc., 1972).
Control Methods
In the case of lagoons or basins for deliberate disposal of sewage
effluents or surface runoff by groundwater recharge, controls specif-
ically pertinent to groundwater protection are essentially self-
generating — the system simply will not work if not properly designed.
Existing engineering and hydrogeologic knowledge would prohibit the
construction of such systems directly in the groundwater; require ade-
quate distance between the infiltrative surface and the groundwater
surface to permit drainage; and prohibit construction in faulted or
fractured strata or in unsuitable soils. Therefore, the first control
measure in groundwater protection from spreading basins is to apply
existing knowledge to their siting and design.
Control of industrial waste discharges to the groundwater is a complex
problem. In a state with a highly organized •water pollution control
agency (eg, California) individual permits are issued on the basis of
adequate design and surveillance programs. Because of the variety of
industrial wastes and of the varied situations in which they occur, con-
trol of groundwater pollution by such wastes depends both upon proper
design of new systems and upon discovery and correction of existing
systems. Methods for controlling groundwater pollution from industrial
lagoons, basins, and pits include:
• Require pretreatment of wastes for removal of at least the
toxic chemicals.
• Require lining with impervious barriers of all lagoons,
basins, and pits that contain noxious fluids. This is the
principal control technique recommended by some agencies,
such as the Delaware River Basin Commission.
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• Use barrier wells, pumped to intercept plumes of con-
taminated ground-water from existing industrial basins
where leakage has occurred. Such wells have been used
successfully, but can be costly to install and operate.
The water removed must be treated before redisposal.
« Ban the use of pits. An example is found in Texas, where
thousands of brine pits were used by the oil industry. The
State found it necessary to ban their use because of the
impossibility of inspecting individual installations and
enforcing a control program.
• Locate and identify unauthorized pits on industrial sites,
on a case-by-case basis, and apply appropriate regulatory
action.
Monitoring Procedures
Lagoons, basins, and pits represent multiple point sources of quality
factors •which may be of significance to groundwater quality. There-
fore, a program involving special monitoring wells in the most criti-
cal situations is a possible approach.
A program of periodic sampling and evaluation of data from existing
wells, selected for their potential to reveal both normal groundwater
quality and point contamination, is another monitoring approach.
Accompanying this should be a program of monitoring of the control
measures themselves to assure, by inspection of sites and of records
required of the operator of approved systems, that groundwater protec
tion is indeed being accomplished.
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References
1. Anon. , "Well Pollution by Chromates in Douglas, Michigan, "
Michigan Water Works News (1947).
2. California State Water Pollution Board, Wastewater Reclamation
in Relation to Groundwater Pollution, Publication No. 6, Sanitary
Engineering Research Laboratory, University of California,
Berkeley (1953).
3. Davids, H. W. , and Lieber, M. , "Underground Water Contamina-
tion by Chromium Wastes, " Water and Sewage Works, Vol. 98,
pp 528-534 (1951).
4. Geraghty & Miller, Inc. , Consultant's report, Port Washington,
New York (1972).
5. Harmond, B. , "Contamination of Groundwater Resources, " Civil
Engineering, Vol. 11, p 343 (1941).
6. Lang, A. , "Pollution of Water Supplies, Especially of Under-
ground Streams, by Chemical Wastes and by Garbage, " Z.
Gesundheitstech. u. Stadtehyg. (Ger.), Vol. 24, No. 5, p 174
(1932).
7. Lang, A. , and Gruns, H. , "On Pollution of Ground-water by
Chemicals, " Gas u. Wasser, Vol. 83, No. 6; Abstract, Journal
American Water Works Association, Vol. 33, p 2075 (1940).
8. McGauhey, P.H. , and Krone, R. B. , Soil Mantle as a Wastewater
Treatment System, Final Report, SERL Report No. 67-11, Sani-
tary Engineering Research Laboratory, University of California,
Berkeley (1967).
9. McGauhey, P. H. , and Winneberger, J. H. , Causes and Prevention
of Failure of Septic-Tank Percolation Systems, Technical Studies
Report, FHA No. 533, Federal Housing Adminstration,
Washington, D. C. (1964).
10. Muller, J. , "Contamination of Groundwater Supplies by Gasoline, "
Gas-u. Wasser, Vol. 93, pp 205-209 (1952).
11. Perlmutter, N. M. , and Lieber, M. , Dispersal of Plating Wastes
and Sewage Contaminants in Ground Water and Surface Water,
South Farmingdale-Massapequa Area, Nassau County, New York,
US Geological Survey Water-Supply Paper 1879-G, 67 pp (1970).
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12. Sayre, A.N., and Stringfield, V. T. , "Artificial Recharge of
Groundwater Reservoirs, " Journal of American Water Works
Association, Vol. 40, pp 1152-1158 (1948).
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SEPTIC SYSTEMS
Scope of the Problem
Septic systems are used in every state of the Union, the heaviest concen-
tration being in suburban subdivisions developed following World War II.
The predominant type of system is the individual household septic tank.
From data available from the Public Health Service and the Federal
Housing Administration, it is estimated that 32 million people were
served by septic tanks in 1970. In addition to the total subsurface perco-
lation systems associated with these installations, there are an unesti-
mated number of summer cabins, Forest Service campgrounds, and
organized group camps which depend upon subsurface disposal of waste-
water, primarily during the summer season.
Although the septic tank -with an associated subsurface percolation system
is the most commonly used type of septic system, raw sewage is still
discharged directly from the plumbing system of the house into cesspools
dug in the ground. The practice is no longer approved for new installa-
tions. Nevertheless, they may be found in the United States wherever
soil conditions make the cesspool feasible. In New York state there are
probably 100, 000 or more such installations. In less populous areas
such as New England, the Southwest, and the Northwest, cesspools are
known to exist. Several thousand such systems discharging into lava
tubes are still in use in Hawaii.
RELATION OF SEPTIC SYSTEMS TO GROUNDWATER. The relationship
between a septic system and the quality of nearby groundwater is gov-
erned by the design and control of the system.
The septic tank is a water -tight basin intended to separate floating and
settleable solids from the liquid fraction of domestic sewage and to dis-
charge this liquid, together with its burden of dissolved and particulate
solids, into the biologically active zone of the soil mantle through a
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subsurface percolation system. The discharge system may be a tile
field, a seepage bed, or an earth-covered sand filter. In some instances,
as in the vicinity of Sacramento, California, where the soil is sandy and
the water table far below the surface, seepage pits are used. These are
drilled holes some 30 inches in diameter extending down to a depth of
25 feet or more, and filled with gravel surrounding a wooden center
frame.
In the cold Northern and Northeast regions of the United States, tile fields
are located below the frost line. This places them below the biologically
active zone of the soil. In low lands, notably in the South, a high ground-
water table makes it necessary to place the percolation system above the
normal ground level. Here a 3-foot deep soil-covered sand bed is used.
It discharges back to standing water in the swamps or road drainage
ditches if it cannot percolate directly into the groundwater.
In a percolation system located in the biologically active zone, biode-
gradable organic matter is stabilized by soil bacteria, particulate matter
is filtered out, and certain ions (e. g. , phosphate) are adsorbed on the
soil. Liquid passing through the active soil zone percolates downward
until it strikes an impervious stratum or joins the groundwater. In the
growing season, a portion, or even all, of the septic tank effluent may be
discharged to the atmosphere by evapotranspiration. Salts not incor-
porated in the plant structure are left in the root zone to be redissolved
and carried downward by percolating water at some other season of the
year. Thus, the purpose of the percolation system is to dispose of
sewage effluents by utilizing the same natural phenomena which lead to
the presence of groundwater.
If the percolation system is below the biologically active zone of the soil,
filtering and adsorption phenomena predominate. Biodegradation in the
system is confined to the partial degradation of organics under anaerobic
conditions.
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History of Septic Systems
The extent to which septic systems may pollute groundwater, and the
•ways in which they may be controlled and monitored, are related to
several historical aspects of these systems. In rural America, the
septic system, whether merely a rock-filled dug hole (cesspool) or a
septic tank with a subsurface percolation field, came into extensive use
as electricity and inexpensive pumping systems became available to rural
families. The isolated rural dweller, however, represents a rather
special case. Normally, he depends for water supply upon his own
shallow well equipped with a jet pump and a small pressure tank. Most
state and county health departments have dealt with the question of ground-
water contamination by specifying some arbitrary minimum horizontal
distance (usually 50 or 100 feet) between the well and the percolation
system as a prerequisite to approval of the septic tank installation. In
terms of groundwater quality, the effect of isolated rural septic systems
is basically negligible because only a small amount of pollutant is intro-
duced to the soil, and at widely separated points. Thus, a great degree
of dilution is achieved by dispersal of inputs.
The use of septic systems in subdivisions following World War II was
attractive to land developers because their objective was to convert land
profitably from single ownership of a large parcel to multiple ownership
of small plots without retaining any residual responsibility for the whole,
especially in the matter of utilities. At that time the design of septic
tank systems had been standardized on the basis of erroneous assump-
tions, codified, and generally regulated by local health departments
(McGauhey and Winneberger, 1964; McGauhey and Krone, 1967; Coulter
et a_l. , I960; Bendixen, e_t aL , 1962). The result was that, through
inadequate knowledge and control, septic tanks with badly constructed
percolation systems were approved for small lots in urban subdivisions,
sometimes of 2, 500 or more houses. The effect was to concentrate a far
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greater amount of wastewater at a local point of infiltration than had
previously existed. However, the potential of these seepage systems to
pollute was often obscured by the failure of percolation systems.
Failure of systems in many areas was known to occur, but this knowledge
was usually confined to the householders or dispersed in the files of
thousands of county health departments. Only after a single agency, the
FHA, became responsible for home loan insurance did it become known
that the failure rate was about 30% within 2 or 3 years. Failure was
characterized by the clogging of soil and the consequent appearance of
wastewater on the surface of the ground. This converted the grounwater
pollution problem to one of surface water during rainy periods.
Environmental Consequences
Two categories of environmental effects which bear upon control measures
may be identified:
• Those -which lead to restrictions on the use of septic systems.
• Those which are inherent in a properly designed and well-
functioning septic system in suitable soil.
Under the first category three situations may be identified. Most common
of these is the failure of percolation systems, which creates a hazard to
health and an unacceptable nuisance as decomposing sewage effluent
appears on the surface of the ground.
The second and more serious situation in the context of groundwater
quality is direct discharge of untreated septic tank or cesspool effluent
into the groundwater through coarse gravel beds, fractured rock, solution
channels, or lava tubes. In some areas of the United States, a local
practice is to cut trenches directly in bedrock and then shatter the rock
with explosives to create drainage channels. Hawaii was mentioned
earlier as an area where cesspools are dug into lava tubes. In all of
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these cases, the groundwater itself often carries for long distances
putrescible sewage solids, bacteria, viruses, and tastes and odors, with
consequent danger to health and impairment of the aesthetic acceptability
of -water.
The third situation is somewhat similar to the second. It occurs when
percolation systems are located below the biologically active zone of the
soil, which typically is only a meter or so in depth. Such systems may
be installed where the frost line is deeper than the biologically active
zone, or they may simply be buried too deeply because of lack of under-
standing of proper construction techniques. (Long Island is perhaps the
most publicized case where percolation systems are commonly to be
found below the biologically active soil zone. ) In such a situation, bio-
degradation in the system is confined to the partial degradation of organics
under anaerobic conditions; the physical phenomena of filtering and adsorp-
tion remain effective, but soluble products of partial breakdown of
organic matter may enter the groundwater and move with it. Tastes and
odors are introduced, and the organic fraction, being biochemically
unstable, remains capable of supporting bacterial growth -when the ground-
water outcrops or is withdrawn through a well.
The second category of environmental effects, those which are inherent
in a properly designed and well-functioning septic system in suitable soil,
has been the subject of much definitive research and is quite well under-
stood. In any specific situation the effects of septic system effluent on
the quality of groundwater depend upon:
• The differences in chemical and physical characteristics
between the local groundwater and the water supply utilized
by owners of septic systems on the overlying land.
• The range of materials added to the water supply by human
use.
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• The changes in the nature of the wastewater occurring in the
septic system and in the biologically active soil through
which it percolates.
• The kind and amounts of material which moves downward
with water percolating to the groundwater.
• The rate and degree of mixing of wastewater and groundwater.
Often the water supply (or carrier water) is less highly mineralized than
groundwater in a specific situation unless the supply is derived directly
from the same local groundwater horizon into which septic system waste-
water is to percolate. This is because water supply is often surface
water imported especially because of its high quality, or is water sub-
jected to ion-exchange or other softening process. The expectation,
therefore, is that the water supply will have essentially the same spec-
trum of ions as groundwater—nitrates, sulfates, carbonates, chlorides,
etc. —but in lesser concentration. Physically it may differ only by being
higher in temperature.
Normally the septic system involves only domestic wastewater; therefore,
materials added by human use will be human body wastes, grease and
organic garbage from the kitchen, and detergents from cleansing activities
in the household. However, miscellaneous pollutants such as water
softener regeneration brines, pesticides, drugs, and solvents may be
added to the septic system by the householder.
The changes in quality occurring in septic tank soil systems have been
extensively studied by many investigators. Briefly, the results of such
studies (McGauhey and Krone, 1967) are as follows:
• Inert and organic particulate matter is effectively removed
by the first few centimeters of soil. Clogging of the infil-
trative surface rather than the quality of the percolated water
is the principal factor in relation to particles.
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• Bacteria behave like other particulate matter in soils and
are removed by straining, sedimentation, entrapment, and
adsorption. They are also subject to die-away in an un-
favorable environment.
• Viruses are removed by soil systems, probably principally
by adsorption, as effectively as bacteria.
• A considerable fraction of the 300 mg/-t total dissolved solids
added to water by domestic use appears as anions and cations
normally found in groundwater. Thus, an increase in the
mineralization of groundwater is to be expected from septic
systems. Under normal conditions of soil pH, phosphates
are effectively removed, •whereas chlorides, nitrates, sul-
fates, and bicarbonates move freely with percolating water.
• Synthetic detergents are effectively destroyed by biodegra-
dation in an active aerobic soil.
The foregoing findings, it should be noted, apply specifically to systems
discharging into the soil mantle of the earth within the biologically active
zone where both physical phenomena and aerobic stabilization of degrad-
able organic matter are effective.
It may be said that at best septic systems increase the total dissolved
mineral solids in groundwater. At worst, they may introduce bacteria,
viruses, and degradable organic compounds as well. The multiple-point
nature of septic system inputs tends to minimize the concentration of
pollutants in any unit of receiving groundwater. In some local situations
the effect may not be measurable by normal analytical tests. In other
local situations such as Long Island, New York, and Fresno, California,
where numerous septic systems are installed in a single subdivision, the
effect on local groundwater has been readily detected (Perlmutter and
Guererra, 1970; Schmidt, 1972).
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Control Methods
Control of the effects of septic systems on ground-water quality must be
considered in three situations:
• Septic tank installations are already in existence.
• New septic tank systems are to be installed.
• No practical alternative to the septic tank is presently
feasible.
Of these situations, the first is the most difficult to deal with because
design is beyond recall and degradation of groundwater may have already
occurred. Of course, if system failure is involved the situation is largely
self-curative. The inability of soils to transmit effluent to groundwater
results in its appearance on the land surface and, if the subdivision
involved is of any significant size, to an early replacement by conven-
tional sewerage. However, if an existing system is functioning satis-
factorily its total contribution of salts to the ground-water can be com-
puted from an analysis of the water supply and the known contribution of
salts from domestic use. The actual immediate effect of any installation
large enough to produce measurable results may be estimated by mon-
itoring the top of the groundwater body. The control program would then
involve mandatory monitoring and judgment of the significance of the
results by competent hydrogeologists. Several control procedures are
applicable.
• Require any existing subdivision subject to septic system
failure or observed by mandatory monitoring to be damaging
to groundwater quality to enter into sewerage districts with
collection and treatment facilities.
• Require householders to connect to a sewer as urban devel-
opment fills in the open land that once set the subdivision
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apart from an urban center, or as land development extends
the populated area beyond the initial subdivision.
• Prohibit the home regeneration of water softeners where
septic systems are used for -waste disposal.
In a situation where new septic tank installations are proposed, possible
measures for control include:
• Require approval of the site and design by competent soil
scientists and engineers before septic systems are approved
for any proposed subdivision, recognizing that simple per-
colation tests (USPHS, 1968) and standard codes offer only
inadequate criteria for the design of a septic system.
• Construct percolation systems by methods which do not
compact the infiltrative surface (McGauhey and Winneberger,
1964), including:
-- No heavy equipment upon infiltrative surfaces.
-- Trenching, boring, or excavating for percolation systems
only when soil moisture is below smearing level.
-- Use of trenching equipment which does not compact
trench sidewalks.
-- Use of classified stone sizes in backfills to produce
"clogging in depth" (McGauhey and Winneberger, 1964).
-- Utilize level bottom trenches with observation -well risers
at end of each tile line.
• Operate septic systems effectively by:
-- Alternately loading and resting one-half the percolation
system; the cycle to be determined by the onset of
ponding in the system at the observation well.
-- Where size of system makes it practicable, loading the
entire infiltrative surface of the system at each cycle
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as uniformly and simultaneously as possible by use of a
dosing siphon.
-- Inspecting and removing scum and grease from septic
tanks annually.
-- Drawing off half of the sludge rather than pumping out the
entire contents of tanks.
• Use of zoning and other land management controls to prevent
septic system installations in unsuitable soils (i. e. , soils
too impervious to accept effluents, or too coarse or frac-
tured to maintain a biological and physical treatment system.
In situations where no practical alternative to septic systems is presently
feasible, the alternatives are to:
1. Prohibit the use of septic tanks regardless of other factors.
2. Limit use of septic systems to the growing season for vege-
tation.
3. Permit the use of septic tanks if soil is suitable, and accept
the consequences in terms of groundwater quality.
4. Permit use of septic systems but restrict the materials
which may be discharged to them, specifically, by prohib-
iting the installation and use of household water softening
units which are regenerated on the site.
5. Permit the use of septic tanks under specific conditions.
The second alternative is applicable to such installations as forest camps,
summer cottages, and summer camps in remote areas where evapo-
transpiration and plant growth consume most of the water and nutrients.
The subsequent pickup of salts in the root zone is done by relatively
large amounts of meteorological water.
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The third alternative is essentially necessary in the case of isolated
dwellings on relatively large plots of land remote from any sewer.
The fifth alternative is an appropriate control measure where soil is suit-
able and good design and operating procedures are followed. Specifically,
it may require that sewers be provided in the streets of a housing devel-
opment and that house owners abandon septic systems and connect to the
sewer -when it is available. A 5- or 10-year maximum permit to use
septic tanks can be specified.
Monitoring Procedures
Assuming that unsatisfactory systems are to be controlled by regulatory
action or replaced as a result of failure, monitoring procedures would
be confined to analyses of percolating wastewater and of the receiving
groundwater, and to requirement of permits and inspection for any non-
permissible softener installations or other connections to the household
plumbing system.
Technologically, the use of tensiometers for sampling percolating water
in both unsaturated and saturated flow conditions is a well-established
routine. Questions to be answered in the case of a subdivision based on
septic systems are who is to make the installations, where are they to
be located, and how continuously are they to be observed and replaced.
The most likely method would be to evaluate the percolate on the basis
of an analysis of the water supply and of a seasonal analysis of percolate
obtained from a short-term field study in one or more septic tank perco-
lation fields. Fundamentally, this procedure yields baseline data but
is not in itself a monitoring system. In general, the monitoring of septic
system percolate is probably an unnecessary and unrewarding procedure.
If groundwater receiving percolate from overlying septic systems is to
be monitored, it is desirable to sample both at the groundwater table and
at greater vertical depths. Bacteria, although they should not be present
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as a result of percolating sewage effluents, tend to concentrate in soil
at the water table. Greases and oils which might be discharged by the
householder also tend to float on the groundwater.
Pragmatically, monitoring may prove to be necessary in order to verify
technological predictions that degradation of groundwater quality will
occur because of prolonged and concentrated use of septic systems. In
Suffolk and Nassau Counties on Long Island, measurements of the degra-
dation of groundwater quality were a major factor in making decisions
to install sewers and treatment plants. (Other factors also enter into
the decision, of course; for example, loss of local recharge may cause
lowering of the water table or head, when sewers collect effluent and
discharge it to a stream or coastal •waters. )
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References
1. Bendixen, T. W. , ^et al. , Study to Develop Practical Design Criteria
for Seepage Pits as a Method of Disposal of Septic-Tank Effluent,
Report to FHA, Robert A. Taft Sanit. Eng. Center, USPHS,
Cincinnati (1962).
2. Coulter, J. B. , etaL , Study of Seepage Beds, Report to FHA,
Robert A. Taft Sanit. Eng. Center, USPHS, Cincinnati (I960).
3. McGauhey, P. H. , and Krone, R. B. , Soil Mantle as a Wastewater
Treatment System, Final Report, SERL Rept. no. 67-11, Sanitary
Engineering Research Lab., Univ. of California, Berkeley (1967).
4. McGauhey, P. H. , and Winneberger, J. H. , Causes and Prevention
of Failure of Septic-Tank Percolation Systems, Tech. Studies
Rept. , FHA no. 533, Federal Housing Administration, Washington,
D. C. (1964).
5. Perlmutter, N. M. , and Guerrera, A. A. , "Detergents and Associ-
ated Contaminants in Ground Water at Three Public-Supply Well
Fields in Southwestern Suffolk County, Long Island, New York, "
U. S. Geol. Survey, Water-Supply Paper 2001-B, 22 pp. (1970).
6. Schmidt, D. E. , "Nitrate in Groundwater of the Fresno-Clovis
Metropolitan Area, California, " Ground Water, v. 10, no. 1,
pp. 50-64 (1972).
7. U. S. Public Health Service, Quad-City Solid Wastes Project—An
Interim Report, July 1, 1966 to May 31, 1967, USPHS, Cincinnati
(1968).
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SPRAYING
History
In the 1950's and early 1960's spray irrigation began to be seriously
considered as a procedure for disposing of wastewater such as the sea-
sonal discharge from fruit and vegetable canneries, or for irrigation of
pasture and forest land and golf courses. Spray irrigation has long
been recognized as an effective method of supplemental irrigation of
crops. It is applicable to all kinds of soils and to any condition of
ground slope, as well as the utilization of small water supplies not
practical under other methods of irrigation (USDA Farmers' Bulletin
No. 1529, 1927). Its principal drawback was that it requires pressure
for operation. As relatively cheap electrical energy became widely
available, the merits of spray irrigation far outweighed pumping costs
and the practice became common on pasture land, alfalfa, sugar cane
and other field crops. Research was directed to evapotranspiration
rates and to changes in soil quality on which depend the most economical
usage of water and the maintenance of optimum soil-water-crop
relationships.
The feasibility of disposing of wastewater or producing useful vegetation
was the subject of many investigations (Bloodgood, et al, 1964; Drake
and Bieri, 1951; Hicks, 1952; Lawton, et al, I960; Luley, 1963; Miller,
1953; Wilson and Beckett, 1968). Some attention was also directed to
the upgrading of water quality via spray irrigation, particularly by the
removal of nutrients from wastewater (Foster, et al, 1965; Hanks, et
al, 1966; Hunt and Peele, 1968; Law, et al, 1969; Parizek, et al, 1967).
Environmental Consequences
A limited amount of data exist on the quality of percolating water from
spray irrigation and on changes in the composition of groundwater
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where such irrigation has been practiced. At Paris, Texas, where
grassland is irrigated with food processing wastes, removals of volatile
solids and BOD range from 92 to 99 percent. Total nitrogen is reduced
by 86 to 93 percent, while 50 to 65 percent of phosphorus is removed
(Anon. , 1970; Law, et al, 1969). No groundwater data are available,
but samples of applied -water taken at a 3-foot depth below the surface
are low in nitrogen and phosphorus and show an increase in salinity with
time. These data are consistent with those for septic systems and
lagoons, based on extensive reported findings (McGauhey and Krone,
1967), with one difference: because spraying rates were adjusted to the
water needs of grasses, nitrogen was taken up by plants. Inasmuch as
the applied wastewater was similar to strong domestic sewage in terms
of BOD, COD, and nutrients, it is evident that the potential of percolate
from spray irrigation of vegetation to change groundwater quality is
reduced in terms of nitrogen as compared to percolate from bare soil.
Of course, if no vegetation were ever harvested, this difference would
in the long run become extremely small.
Reduction in nitrogen by field crops and trees occurred also in a
demonstration study of spray irrigation with sewage effluent made by
the Pennsylvania State University (Parizek, et al, 1967; Pennypacker,
et al, 1967).
In an earlier study of spray irrigation of forest land with sewage, most
of the nitrogen in the sewage appeared in the groundwater (Larson,
1960; McGauhey, et al, 1963), as indicated in Table 2-13.
The Pennsylvania State study (Parizek, et al, 1967) included both water
quality changes and groundwater effects of spray irrigation by a system
shown schematically in Figure 2-5. A similar diagram of monitoring
installations is shown in Figure 2-6.
2-83
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Table 2-13. Groundwater composition before and after
spray irrigation with sewage (Larson, I960).
Total Hardness
Alkalinity
Chlorides
Nitrate Nitrogen
Nitrite Nitrogen
Ammonia Nitrogen
Organic
Total Nitrogen
Total Phosphorus
Groundwater Level
*Kjeldahl Nitrogen
14 October 1955 21
Before Spraying
300
310
9
1
0. 19
1.4
2. 6
0. 6
11' 10. 5" below
top of well
(Ammonia plus organic)
November 1958
After Spraying
420
320
130
31. 0
2. 2*
31. 0
2. 9
8' 9. 5" below
top of well
Twelve inches of soil on the forest floor removed 95-98 percent of the
ABS and 99 percent of the phosphorus. An increase in nitrate nitrogen
appeared in the percolate. Thus, the results of spray irrigation com-
pare favorably with those of surface ponds or subsurface percolation
systems (McGauhey and Krone, 1967); however, a takeup of nitrogen by
field crops and forest reduced the concentration of nitrogen moving with
percolating water. Water quality measurements from deep wells
showed the water at the irrigated site to be as good or better than that
in off-site wells.
Existing evidence leads to the conclusions that:
• Spray irrigation of wastewater carrying plant and animal
residues in varying degrees of biodegradation may have
no measurable effect on nitrogen in groundwater if the
system is operated as an evapotranspiration-nutrient
stripping procedure.
2-84
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Of.
0
3
^
"5
I
o
c
o
*
Ground Water
Recharge
S to rag
Discharge
to Creeks,
Springs,
and Wells
Ground Water
Reservoir
oo
Ln
Figure 2-5. The wastewater renovation and conservation cycle
(Parizek, et al, 1967).
-------
Mixed Hardwoods
Red Pine
Abandoned Fields
Agronomic Crops H
Bedrock
Dolomite and Sandstones
of Gatesburg Formation
A. Throughfall gauge
B. Lysimeters (In root zone at depth of 1 i inches to 4 feet).
C. Soil Moisture Access Tubes (To measure changes in
soil moisture— 8 to 20 feet deep).
D. Sand-point Wells (completed in the weathered
mantle at depths from 6 to 52 feet).
E. Deep Water-table Wells (Contain submergible or
piston pumps, 250 to 300 feet deep).
F. Trench with pan lysimeters at one foot intervals to
depths 6 and 16 feet.
G. Suction lysimeters, 6 inches to 26 feet in depth
H. Weather Station
Figure 2-6. Schematic of various types of monitoring
installations (Parizek, et al, 1967).
2-86
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• Over a period of time, leaching of salts from the root zone
may become necessary. Normally, rainfall will carry such
salts down to the groundwater. The effect on groundwater
quality then depends upon the quality of the water supply
from which the •waste derives, and the amount and nature
of soluble salts after any pretreatment of the wastewater
and passage through the biologically active soil mantle.
• Fundamentally, spray irrigation is but one of several •ways
of applying wastewater to soil for percolation to the
groundwater. It differs from lagoons and underground
systems in that it affords a greater opportunity for waste-
water to contaminate surface runoff during rainfall periods.
Future Prospects
Spraying as a method of wastewater disposal, nutrient removal, and
•water reclamation can be expected to increase in the future. Federal
objectives envision that all sewage must be treated to at least a secon-
dary level within the next few years. As the quality of treated waste-
water increases so does it usefulness to man. There is a growing
public mood of resource conservation, and more stringent attempts to
achieve a condition of ''no pollutant discharge" to surface waters. This
leaves the land as the receptor of used -water or, at least, of the soluble
minerals which differentiate it from meteorological waters. Land dis-
posal of either wastewater or its constituents can only mean that
groundwater becomes the sink, unless special precautions to protect it
are taken. One such system is to incorporate as many constituents of
•wastewater as possible into harvestable vegetation, or to tie it up in the
soil and return the •water directly to the atmosphere by evapotranspira-
tion. Thus, spraying leads to a reduction in the potential of wastewater
to affect the quality of groundwater. The potential of spraying to
accomplish this result justifies its further practice.
2-87
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Control Methods
Considering spraying as but one of several methods of applying
wastewater to soil, no unique procedures for controlling its contribu-
tion to groundwater quality are evident. In the broader sense of mini-
mizing the effects of land disposal of wastewater on groundwater qual-
ity, spraying might be recommended instead of surface ponding or sub-
surface irrigation because of its potential to remove nitrogen during
the growing season and, simultaneously, to minimize the amount of
water percolating to the groundwater. Offsetting this, however, are
two factors:
9 The possibility of sprayed water running off to surface
waters, especially during storms, and so violating
quality requirements established for surface waters.
« The ultimate movement of salts from the root zone to
groundwater in amounts essentially the same as from
surface spreading except for nitrogen and such other
minerals as are taken up by vegetation.
Specific control measures which might be applied directly to wastewater
generally serve to reduce the potential of spraying to affect groundwater
quality. Eliminating the potential entirely requires a combination of
partial demineralization, siting of the spray system, and operation of
the system so that the sprayed water closely approximates the native
groundwater in chemical constituents.
Specific control measures which might be applied directly to wastewater
include:
• Limitation of the type of wastewater which can be applied
to land to those which carry products of the natural cycle
of growth and decay of organic matter; that is, to domes-
tic sewage effluents and certain food and natural fiber
2-88
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processing wastes as contrasted with industrial wastes
carrying chemicals and metal ions.
• Siting the spray operation where soil and geological
conditions are favorable to land disposal systems.
• Operating the spray system to maintain a treatment
potential of the aerobic soil mantle. This is especially
important with cannery wastes because the startup time
of any biological treatment system other than the soil
system is too long to be useful in treating seasonal
cannery wastes alone.
Control measures such as the foregoing confine the quality factors
reaching the groundwater to those in the water supply, plus those added
by biodegradation, and minus those which may be taken up by vegeta-
tion. The result may be a percolating water of better or poorer quality
than the native groundwater, depending upon the total dissolved solids
content of the groundwater and that of the applied (sprayed) water.
2-89
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References
1. Anon. , "Wastewater Disposal Enhances an Area Ecology, "
Industrial Waste Engineering (1970).
2. Bloodgood, D. E. , et al. , "Spray Irrigation of Paper Mill Waste, "
Proceedings 15th Oklahoma Industrial Waste Conference, Okla-
homa State University, Stillwater (1964).
3. Drake, J. A. , and Bieri, F. K. , Disposal of Liquid Wastes by the
Irrigation Method at Vegetable Canning Plants in Minnesota 1948 —
1950, Purdue University, Indiana, Engineering Extension Depart-
ment, Series No. 76:70-79 (1951).
4. Foster, H. B. , et al, "Nutrient Removal by Effluent Spraying, "
Journal Sanitary Engineering Division, American Society of Civil
Engineers, Vol. 91, No. SA6 (1965).
5. Hanks, F. J. , et al, Hydrologic and Quality Effects of Disposal of
Peach Cannery Waste on a Cecil Sandy Clay Loam, Clemson
University, So. Carolina, Agr. Eng. Res. Series No. 9 (1966).
6. Hicks, W. M. , Disposal of Fruit Cannery Wastes by Spray
Irrigation, Purdue University, Indiana, Engineering Extension
Department Series No. 79:130-132 (1952).
7. Hunt, P.O., and Peele, T.C., "Organic Matter Removal From
Liquid Peach Waste by Percolation Through Soil and Interrela-
tions with Plant Growth and Soil Properties, " Agronomy Journal,
Vol. 60 (1968).
8. Larson, W. G. , "Spray Irrigation for the Removal of Nutrients in
Sewage Treatment Plant Effluents as Practiced at Detroit Lakes,
Minnesota, " Trans. I960 Seminar, Taft Sanitary Engineering
Center, Technical Report No. W61-3 (I960).
9. Law, J.P. , Jr., et al, "Nutrient Removal From Cannery Wastes
by Spray Irrigation of Grassland, " Water Pollution Control
Research Series 16080-11/69 (1969).
10. Lawton, G. W. , et al, Effectiveness of Spray Irrigation as a
Method for the Disposal of Dairy Wastes, University of Wisconsin,
Engineering Exp. Sta. Report No. 15, Agr. Exp. Sta. Research
Report No. 6 (I960).
2-90
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11. Luley, H. G. , "Spray Irrigation of Vegetable and Fruit
Processing Wastes, " Journal Water Pollution Ccntrol Fed. , Vol.
35, No. 10, pp 1252-1261 1963).
12. Miller, P. E. , Spray Irrigation at Morgan Packing Company,
Purdue University, Indiana, Engineering Extension Department
Series No. 83:284-287 (1953).
13. McGauhey, P. H. , et al, Comprehensive Study on Protection of
Water Resources of Lake Tahoe Basin Through Controlled Waste
Disposal, Lake Tahoe Area Council, Board of Consultants Report
(1963).
14. McGauhey, P. H. , and Krone, R. B. , Soil Mantle as a Wastewater
Treatment System, Final Report, SERL Report No. 67-11, Sani-
tary Engineering Research Laboratory, University of California,
Berkeley (1967).
15. Parizek, R. R. , et al, Waste Water Renovation and Conservation,
The Pennsylvania State University Studies No. 23 (1967)
16. Pennypacker, S. P. , et al, "Renovation of Waste Water Effluent
by Irrigation of Forest Land, " Journal Water Pollution Control
Fed. , Vol. 39, pp 285-296 (1967).
17. USDA Farmers' Bulletin No. 1529, "Spray Irrigation in the
Eastern States" (1927).
18. Wilson, C.W. , and Beckett, F. E. , "Municipal Sewage Effluent
for Irrigation, " Proceedings of Symposium at Louisiana Poly-
technic Institute (1968).
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STREAM BEDS
Scope of the Problem
Disposal of partly treated sewage and industrial wastes in the beds of
intermittent and ephemeral streams is practiced mainly in the arid and
semi-arid regions of the southwestern United States, particularly in
California (Calif, State Water Quality Control Board, 1966; Calif.
Dept. of Water Resources, 1966) and Arizona (Bouwer, 1968), where the
more conventional method of disposal directly into a flowing stream may
be impractical. Stormwater runoff also is discharged into beds of inter-
mittent streams in many parts of the country. A benefit of all these
procedures is the replenishment of the groundwater resources.
Effluent usually either percolates into the ground or is evaporated before
it travels a great distance down the stream channel. During storms,
the channel may contain substantial amounts of runoff, which scour out
the bottom materials of the stream bed, carry away accumulated silts
from natural and sewage sources, and dilute the contaminated water in
and beneath the stream. Wastewater that infiltrates the stream bed in
one reach may surface again down-gradient in the stream flow.
The infiltrative capacity of a stream bed varies with the nature of the
geologic materials it contains. In reaches where the bottom materials
consist of sand and gravel, infiltration is generally at a maximum
(McGauhey and Krone, 1967). In other places, where pools and ponds
may have previously clogged the bed with organic material and silt, the
infiltrative capacity may be substantially reduced. Seasonal storm-
water inflow that scours and cleanses the stream bed will restore
its infiltrative capacity.
In contrast to the conditions described above, stream beds in the humid
eastern part of the country are rarely dry except in the extreme head-
water reaches. However, experiments have been planned for recharging
tertiary-treated sewage effluent in the headwaters of several streams in
2-92
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southwestern Suffolk County, New York, to maintain the average flow of
the streams for aesthetic and recreational purposes. These streams
presently are fed by groundwater inflow, but it is anticipated that con-
struction of a major sewer system in the next ten years will eliminate
thousands of cesspools whose effluent is now a major source of ground-
water recharge. It is expected that this reduction in recharge will result
in a decline of the water table and in a substantial, if not a complete,
loss of flow in the headwaters of the streams in the area.
Environmental Consequences
Disposal of wastes into stream beds may cause contamination of an
underlying shallow aquifer. Generally, stream-bed percolation of wastes
tends to increase the overall salinity of shallow groundwater. In those
areas that depend partly or totally on groundwater for water supply, the
polluted water may eventually arrive at pumping wells whose cones of
influence intercept water from beneath the stream. The possibility of
pollution is less for wells tapping deeper aquifers than for shallow aquifers,
because of separation by confining beds of low permeability.
Even if there are no pumping -wells in the vicinity, the wastes will tend
to move down-gradient in the main body of groundwater and may eventually
enter a stream and reappear as surface water. Such seepage of wastes
that contain high concentrations of nutrients can cause excessive algae
growth in the stream and thereby render the surface water unsuitable for
various uses.
Inadequate pre-treatment or inadequate natural treatment during the
movement of the water through the soil zone, or rapid leakage into
shallow fractured rock, may introduce bacteria or toxic chemical sub-
stances into the aquifer.
A rise of the water table in the stream bed due to recharge may cause
formation of pools and swamps containing partly treated wastewater,
2-93
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which may become septic, give off odors, and attract flies, mosquitoes,
and miscellaneous vermin.
Nature of the Pollutants
The pollutants that enter an aquifer beneath a stream bed depend on the
character of the wastes (domestic, industrial, or both), the type of
stream bed material, the depth to the water table, and the type of treat-
ment given to the wastes. In the case of domestic wastes, the potential
pollutants include chlorides, organic compounds, nitrogen compounds
in various stages of oxidation, phosphates, synthetic detergents, bacteria,
viruses, and perhaps pesticides. If industrial or agricultural wastes
are included, the spectrum of possible pollutants becomes very broad.
From a general standpoint, those of greatest concern include heavy
metals such as cadmium and chromium, and organics such as phenolics
and polychlorinated biphenyls.
Pollution Movement
The principal route of the contaminated wastes is by downward percola-
tion beneath the stream bed to the water table below the disposal area.
From there the contaminated water moves down-gradient in the upper
part of the main body of groundwater and may discharge into the stream
at and below the start of flow in the channel (Figure 2-7). Where heavy
infiltration causes the water table to rise close to the land surface or
where a perched water table is created above beds of silt or clay in the
unsaturated zone above the main water table, wastewater may emerge at
the land surface and form local ponds or swampy areas.
Another possible condition involves a thin overburden containing a shallow
water table in highly permeable beds of sand and gravel or a thin over-
burden underlain by fractured or fissured rock. In these cases, the
wastes move down essentially directly into the groundwater with little or
no natural treatment and may reach a stream or nearby wells with little
2-94
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Figure 2-7. Pattern of flow at and beneath a liquid
waste-disposal area in a dry stream bed.
Shaded area shows hypothetical path of
movement of the contaminated water.
Arrows indicate the direction of ground-
water flow.
change other than dilution. This short flow path is particularly hazardous
if pathogens are present in the waste. Where the depth to the water table
below a stream bed is substantial, bacteria and organic chemicals may
be largely removed by biochemical degradation during downward move-
ment through the biologically active zone. However, it is likely that most
dissolved inorganic constituents will eventually reach the water table.
Control Methods
To control pollution, most wastes before disposal into dry stream beds
should be pre-treated to a level equivalent to secondary treatment or
higher. A second line of defense is the natural renovation of wastewater
in the ground by a combination of biological, physical, and chemical reac-
tions. Thus, an important consideration for site selection is the ability
of the earth materials to treat the wastes properly (Pennsylvania Depart-
ment of Environmental Resources, 1972).
In unconsolidated materials such as sand and gravel, bacteria are com-
monly removed by natural phenomena. Viruses are also generally
removed by movement through these materials, but the extent and mech-
anisms are still imperfectly known. In rock aquifers, and especially in
some limestones, bacteria may travel long distances.
2-95
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Dissolved organic constituents in domestic and some industrial wastes
are removed or reduced in concentration by the natural flora of the soil,
greatly reducing or eliminating biochemical oxygen demand of the wastes.
At the same time, ammonia nitrogen, nitrite, and organic nitrogen are
largely oxidized to nitrate, which may be a health hazard where the con-
centration exceeds 45 mg/-t as nitrate. A substantial reduction in total
nitrogen may occur, depending upon the site and its operation (Bouwer,
1970).
Phosphates are commonly reduced or removed by direct chemical reac-
tion and by adsorption. Heavy metals may be removed from industrial
wastes by ion exchange, but the exchange capacity of individual soils
varies widely. Chlorides move through the subsurface environment and
often are used as tracers in determining the movement and concentra-
tion of wastes in the groundwater.
The selection of suitable waste-disposal sites in stream beds is also a
key step in minimizing the pollution opportunity. The major factors in
site selection (adapted from Bond and others, 1972) are summarized
below:
• Soils. A knowledge of the detailed characteristics and depth
of soil is critical in estimating the degree of natural renova-
tion the wastewater will receive before reaching the water
table. Deep, well drained, loamy soils are preferable.
Clayey soils retard infiltrating water but maximize adsorp-
tion, while coarse soils may permit such rapid percolation
that renovation is incomplete.
• Hydrology. The basic hydrologic considerations in evaluating
a site are the depth of the water table, the direction and rate
of movement of the groundwater, the location of induced or
natural discharge, and possible changes in groundwater flow
2-96
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that may be caused by the buildup of a recharge mound under
the stream bed. Additionally, the water table fluctuates
seasonally, and high water tables, regardless of their cause,
can lessen the effectiveness of the stream bed as a mech-
anism for natural treatment of the wastes. A minimum depth
to the water table of 10 feet below land surface is commonly
recommended (Pennsylvania Department of Environmental
Resources, 1972). However, upward mounding in some
hydrogeologic environments may require greater initial depths
to the water table.
Geology. The geologic characteristics of the overburden and
the underlying rock have a very important bearing upon the
suitability of a site. The overburden and the rock must be
sufficiently permeable to permit continued downward perco-
lation of the wastewater. Otherwise perched water tables
will form, and the aerobic zone will be reduced and possibly
eliminated.
Reaction of the effluent with the overburden. Effluents have
different constituents; the chemical reactions that occur
between those constituents and the constituents of the over-
burden should be determined experimentally before disposal
operations are started.
Topography. The effluent should spread freely and should not
accumulate in puddles or ponds.
Rate of infiltration. The infiltrative capacity of the soils to
accept wastewater should be determined by testing and ex-
perimentation, as this will help to determine the required
size of the disposal area. Proper maintenance of the stream
bed materials is essential to sustain aerobic conditions.
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If retention or stabilization ponds are used, with periodic discharge of
effluent, the above listed criteria still should be considered. In addition,
the ponds should be designed so that they will provide aerobic conditions.
For example, intermittent application of the waste effluent and rotation
of the disposal of the wastes from one area to another are essential to
reoxygenation of the soil, and hence to the maintenance of an aerobic
environment. Application rates must be kept at levels that do not exceed
the infiltration capacity of the soil. Vegetative cover will normally
improve infiltration, but may require periodic harvesting or burning.
Harrowing of the disposal areas may be desirable, should the surface
layer become compacted or clogged.
Monitoring Procedures
Monitoring wells installed beneath and near the stream channel may be
used to determine the subsurface paths of flow and changes in quality as
the water moves down-gradient from the area of infiltration. Monitoring
wells also may be installed between the stream channel and nearby supply
wells to provide advance warning of possible movement of contaminated
water toward the wells.
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References
1. Bond, J. E. , Williams, R. E. , and Shadid, O. , "Delineation of
Areas for Terrestrial Disposal of Waste Water, " Water Resources
Research, v. 8, no. 6 (1972).
2. Bouwer, H. , "Putting Waste Water to Beneficial Use The Flush-
ing Meadows Project, " Proc. 12th Annual Arizona Watershed
Symposium, pp. 25-30 (1968).
3. Bouwer, H. , "Water-Quality Aspects of Intermittent Systems Using
Secondary Sewage Effluent, " Artificial Recharge Conference,
Univ. of Reading, England, Water Research Assoc. , Medmenham,
England (1970).
4. California Department of Water Resources, Planned Utilization of
Ground Water Basins: Coastal Plain of Los Angeles County,
California Resources Agency, Bull. 104, 435 pp. (1966).
5. California State Water Quality Control Board, Waste Water Recla-
mation at Whittier Narrows, California Resources Agency, Publ.
no. 33, 100 pp. (1966).
6. McGauhey, P. H. , and Krone, R. B. , Soil Mantle as a Waste Water
Treatment System, Final Report, SERL Rept. no. 67-11, Sanitary
Eng. Research Lab., Univ. of California, Berkeley (1967).
7. Pennsylvania Dept. of Environmental Resources, Spray Irrigation
Manual, Bur. of Water Quality Management, Publ. no. 31, 16 pp.
(1972).
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LANDFILLS
The Matter of Definition
To evaluate the effects of land disposal of solid wastes in the context of
"landfills, " it is necessary to recognize an unfortunate lack of distinc-
tion between the properly designed and constructed sanitary landfill and
the variety of operations that are properly classed as refuse dumps.
Therefore, a landfill is herein defined as any land area dedicated or
abandoned to the deposit of urban solid waste regardless of how it is
operated or •whether or not a subsurface excavation is actually involved.
Urban, or municipal, solid waste is considered to include household,
commercial, and industrial wastes which the public assumes responsi-
bility for collecting. However, commercial solid waste and industrial
solid wastes presently collected and hauled privately may be discharged
into a public landfill, along with municipal wastes and refuse which the
citizen himself delivers.
Few citizens have ever seen a good landfill because only 8 percent of
municipal solid wastes go into satisfactory landfills, whereas 75 per-
cent goes into refuse dumps which are environmentally unsatisfactory.
The remaining 17 percent is incinerated or composted. The term land-
fill, therefore, generally evokes the image of a dump and, by inference,
the individual and then the public agency often assumes as an article of
faith that leachate from landfills is an ever-present environmental evil.
As a matter of fact, leaching from a modern well-designed sanitary
landfill is more fancied than real, whereas leaching from open dumps
may be both real and extensive. Therefore, in dealing with the problem
of protecting groundwater quality through control of leachate from
refuse, a distinction must be made between control measures built into
new or existing well-engineered landfills and control measures appro-
priate to existing dumps and poorly-engineered landfills.
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Environmental Consequences
The potential hazard of landfills to groundwater quality via leachate is
a function of the total amount of waste generated, its areal distribution,
the composition of the waste itself, and the siting, design, and opera-
tion of the fill. The US Environmental Protection Agency estimated
that in 1969 urban solid waste totaled 250 million tons per year, while
industrial solid waste was about 110 million tons. Various estimates
of this total for 1972 are about one ton per capita per year — almost 6
pounds per person per day. In 1970 (EPA, 1972) there were some
16,000 authorized land disposal sites, and perhaps 10 times that many
unauthorized dumping grounds. Because wastes are generated and
disposed of where people are, the pattern of population distribution
gives a clue to the location and intensity of landfill practice.
Typical values of components of solid wastes collected in urban
communities are shown in Table 2-14. From Table 2-14 it may be
concluded that slightly over 70 percent of domestic refuse is biodegrad-
able organic matter of which about three-quarters (50 percent of total
waste) is paper and wood. An additional fraction ranging from 1 to 15
percent in the table involves materials which might include some leach-
ate solids such as ashes and certain soils. Studies made in Berkeley,
California in 1952 and repeated for the same area in 1967 (Golueke and
McGauhey, 1967) verify this conclusion and show that the percentages
of individual components changed very little over the 15-year period.
Data on the amount and composition of industrial solid wastes and on its
disposal are less extensive. A survey (Manufacturing Chemists Asso-
ciation, 1967) of 991 chemical plants, of which 889 were production
facilities is reported in Table 2-15. It shows that 75 percent of waste
solids were non-combustible process solids and that 71 percent of the
total was disposed of by landfill on company-owned property. No data
are at hand on the composition of these wastes but it must be presumed
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I
I—'
o
Table 2-14. Components of domestic solid waste
(expressed as percentages of total).
Paper Products
Food Wastes
Garden Wastes
Plastics
Cloth, Leather
Rags, Rubber
Wood
Rocks, Dirt
Miscellaneous
Unclassified
Metals
Glass and
Ceramics
, .....
Santa
Claraa
50
12
9
1
4
2
7
8
7
Los
Angeles
41
6
21
2
2
2
12
6
8
Quad-
Louis- Cities Purdue
villec N.J.d Univ.6
60 45 42
18 i 12
1 12
2 1
--52
1 2
3 10 15
998
10 6 6
23
Citiesf
46
17
10
1
4
3
1
9
9
Madison
Wis.I
52
10
8
2
4
2
—
7
15
National
Avg.h
50
15
5.
3J
2k
2
i
]
7
8
8
; a.
; b-
c.
d.
i e.
}
EPA, 1970; University of California
Bergman, 1972
EPA, 1970; University of Louisville
US Public Health Service, 1968
Bell, 1963
Niessen and Chanskey, 1970
g. Ham, 1971
h. Salvato, et al, 1971
i. Total 3 categories sa 23 percent
j. Includes rubber
k. Rubber included with plastics
-------
that some fraction of the total was leachable if conditions leading to
leaching occurred.
Table 2-15. Landfill disposal of chemical process wastes.
Type of Waste
Process solids, non-combustible
Process solids, combustible
Containers, non- combustible
Containers, combustible
Fly ash from fuel combustion
Other, or unspecified
Disposal Method
Landfill on company property
Landfill away from company
property
Incineration, with heat recovery
Incineration, without heat recovery
Open dump burning
Contracted disposal
Other, or unspecified
Total Per Year
(Thousands of
Tons)
8,404
573
64
168
1,587
466
11,262
8,067
520
92
231
109
1, 627
616
11,262
Percent
Total
75
5
1
1
14
4
71
5
1
2
1
15
6
Leaching of Landfills
Leaching of landfills with consequent contributions to underlying
groundwater depends upon several factors. These, together with
measures for control were summarized in 1971 (Salvato, et al, 1971).
If a landfill is to produce leachate there must be some source of water
moving through the fill material. Possible sources include (1) precipi-
tation, (2) moisture content of refuse, (3) surface water infiltrating into
2-103
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the fill, (4) percolating water entering the fill from adjacent land area,
or (5) ground-water in contact with the fill. In any event, leachate is not
produced in a landfill until at least some significant portion of the fill
material reaches field capacity. To accomplish this, 1. 62 inches of
water per foot of depth of fill is reported to be necessary (Qasim and
Burchinall, 1970). This value is far in excess of that which might be
produced from a typical mixed refuse. Moisture in refuse is about 20
percent by weight (Kaiser, 1966; Bell, 1963). Because of the high
paper content and the relatively inert material shown in the typical
analyses, Table 2-14, only a small amount of moisture is released by
the decomposition of the organic solids in refuse. A composite sample
(Bell, 1963) of an average municipal refuse is shown in Table 2-16.
Table 2-16. Composition of municipal refuse.
Moisture
Cellulose, sugar, starch
Lipids
Protein - 6. 25N
Other organics
Inerts
Percent
20. 73
46. 63
4. 50
2. 06
1. 15
24. 93
100.00
To induce composting, a moisture content of 50 to 60 percent is
required, hence a fill having no source of moisture except that of urban
refuse will decompose very slowly and produce little if any leachate.
On the other hand, if a fill were made of fruits and vegetables having
80 to 90 percent moisture, anaerobic decomposition would proceed
rapidly and leachate would be produced. Thus, landfill is not recom-
mended for cannery wastes alone.
2-104
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Percolating water entering a landfill from surrounding land is not
likely in a proper landfill. Even at the 750-850 pounds per cubic yard
compaction attained in normal landfills, the fill material is difficult to
saturate.
If other sources of •water are excluded from a landfill by employing
procedures described in a later section, the production of leachate in a
well designed and managed landfill can be effectively eliminated. In
that a proper landfill not intersecting the ground-water will not cause
water quality impairment for either domestic or irrigation use. Sub-
sequent reports (Sumner, 1972) of test borings around landfills dating
back as far as 50 years in England showed no evidence of groundwater
pollution as a result of leaching. Similarly, no evidence was found
Stolp, 19721 in Holland that past landfilling has been a source of pollu-
tion of groundwater. Evidence reported from Illinois and Minnesota
(Anon. , 1973; Saxon's River Conference, 1972) is that leaching did not
contaminate groundwater in two major fills built within the groundwater
itself. Compaction of fill material, clogging of fill area walls
(McGauhey and Krone, 1967), and balance of hydrostatic pressure
cause groundwater to flow around the fill rather than through it.
Absence of leaching as an important problem is characteristic of
landfills sites, engineered, and constructed in accord with best current
technology. In this category are most of the sanitary landfills compris-
ing 8 percent of the present land disposal situations, and presumably
those yet to be built in the future. The 75 percent of urban refuse
placed in dumps which in varying degrees are open to external sources
of water are likely to produce leachate in significant amounts. It is
estimated (Salvato, et al, 1971) that of 49 inches annual rainfall in New
York, 45 percent will infiltrate into an unsealed and unprotected dump.
At some seasons of the year up to 70 percent of the infiltrated water
may be returned to the atmosphere by evapotranspiration. The
2-105
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remainder, and at times all, of the infiltrate will percolate through
the landfill. If the fill is in a subsurface excavation, this percolate
will move downward to the groundwater at a rate governed by the
degree of clogging of the underlying and surrounding soil. Clogging,
however, may reduce permeability at the infiltrative surface
(McGauhey and Winneberger, 1964; McGauhey and Krone, 1967); it can-
not be assumed that the landfill will long discharge leachate at an
appreciable rate. It may tend to become essentially a basin filled with
saturated refuse and soil. Further rainfall will then run off the fill
surface without coming in contact with refuse. However, if leachate is
produced within a fill and soil clogging controls its escape to the
groundwater, a large fill area even at a low rate of movement into the
underlying strata could with time discharge a significant volume of
leachate.
Not all unsatisfactory landfills are built in subsurface excavations.
Many are in ravines or above the original land surface. In these cases
clogging beneath the fill is not the controlling factor. Infiltrated water
outcrops laterally on the surface as leachate. There it flows on the
soil surface over such an area as necessary for infiltration, or runs off
in the surface stream system.
The amount of water which may pass through an open dump is
significant. Once field capacity is reached, 36 inches of rainfall per
year upon an open shredded refuse fill would (theoretically) percolate
about 1 million gallons of contaminated water per acre (Salvato, et al,
1971). In reality, however, this amount would be significantly reduced
by evaporation from the fill surface.
A secondary leaching phenomenon associated with all types of landfills
not subjected to specific controls is the result of CO generated in the
LJ
fill being forced outward into the surrounding soil. When picked up by
percolating rainwater, this increases the aggressiveness of water to
2-106
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limestones and dolomites and so increases the hardness of groundwater.
A refuse of the composition shown in Table 2-16 is theoretically capa-
ble of producing 2. 7 cubic feet of CO,, per pound of refuse (Anderson
and Callinan, 1969). However, the balance of nutrients, the moisture,
and other environmental factors are unlikely to exist over the time
span necessary for any such complete destruction of the carbonaceous
fraction of refuse.
Nature and Amount of Leachate
Data on the analysis of leachate vary widely. Much of it comes from
short-term lysimeter studies in which researchers had to make special
effects to saturate the refuse so as to produce maximum leaching.
Thereafter, experiments were often terminated before the leaching rate
reached an equilibrium. Data on leachate from several sources are
summarized in Table 2-17 (Salvato, et al, 1971).
Table 2-17 indicates •what many observers have reported: the initial
values of BOD and COD are always high. Studies of operating landfills
(Emrich and Landon, 1969; California State Water Pollution Control
Board, 1954) show constituents of leachate to include:
COD ~ 8, 000-10, 000 ing/-I
BOD ~ 2, 500 mg/-t
Iron ~ 600 mg/-L
Chloride ~ 250 m.g/1
Table 2-17 also shows hardness, alkalinity, and some ions to be
significantly increased. The California data also show that continuous
flow through one acre-foot of newly deposited refuse might leach out
during the first year approximately:
Sodium plus potassium 1. 5 tons
Calcium plus magnesium 1. 0 tons
Chloride 0. 91 tons
2-10'
-------
o
OO
Table 2-17. Leachate composition.
Determination (mg/-i)
PH
Total hardness (CaCO2)
Iron total
Sodium
Potassium
Sulfate
Chloride
Nitrate
i
Alkalinity as CaCo2
Ammonia nitrogen
Organic nitrogen
COD
BOD
Total dissolved solids
a. No age of fill specified
5 is from 3 -year old fl
b. Data from Los Angeles
c. Data from Emrich and
lb
5. 6
8, 120
305
1, 805
1, 860
630
2, 240
no result
8, 100
815
550
no result
32,400
no result
for Sources 1 •
.1, 6 is from 1
County (1968)
Landon (1969).
2^
5. 9
3, 260
336
350
655
1, 220
no result
5
1, 710
141
152
1, 130
7,050
9, 190
-3, Source
5 -year old
Source3-
3b 4c 5c 6c
8. 3
537 8,700 500
219 1,000
600
no result
99 940 24
300 2,000 1,000 220
18
1, 290
no result
no result
no result 750, 000
no result 720, 000
2, 000 11, 254 2, 075
4 is initial leachate composition,
fill.
-------
Sulfate 0. 23 tons
Bicarbonates 3. 9 tons
Rates for subsequent years were expected to be greatly reduced.
Field studies of the amount and quality of leachate through well-
designed fills have been made by the Los Angeles County Sanitation
Districts. At their Mission Canyon Landfill, underdrains were
installed beneath two large fills to entrap leachate (Dair, 1967;
Meichtry, 1971). One was installed in 1963; the other in 1968. At the
time of Meichtry's report (1971) the first of these two had produced
nothing but odorous gases although the fill was heavily irrigated from
1968 onward. The second, deeper fill produced odorous gases but no
leachate until March 1968 when 4. 35 inches of rain fell in 24 hours.
On that occasion 213 gallons of leachate were collected. Flow then
continued at a rate of about 1, 500 gallons per month. Periodic analysis
of the leachate indicated that a spring in the canyon wall beneath the
fill, rather than infiltration of the fill, was the source.
Table 2-18 shows both the initial composition of the leachate and its
reduction with time over a 3-year period. The table shows a decrease
in concentration of most constituents of the leachate with time. This
same phenomenon has been observed in comparing a 27-year old
abandoned fill with an active fill (Emrich and Landon, 1969).
Pilot studies were made in 1964 to 1966 (Merz and Stone, 1967; Dair,
1967; and Meichtry, 1971) to study the effects of rainfall and irrigation
on landfill leaching. Two cells 50 feet square at the bottom and sloped
to the top were filled with a single 19-foot lift of refuse, plus a two-
foot earth cover. Devices to collect leachate at various depths were
installed. One was subjected to simulated rainfall; the other to irriga-
tion of turf. After 27 months and 130 inches of rainfall no leachate
appeared in the rainfall cell. A small amount of water appeared in the
2-109
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topmost cell of the irrigated system at 27 months and 169 inches of
applied water.
Table 2-18. Change in leachate analysis with time
(Meichtry, 1971).
Leachate Analysis
Constituent
PH
Total Solids, mg/-t
Suspended Solids, mg/-t
Dissolved Solids, mg/-L
Total Hardness, mg/-L CaCO3
Calcium., mg/-t CaCO^
Magnesium, mg/-L CaCO,
Total Alkalinity, mg/-t CaCOj
Ammonia, mg/-t N
Organic Nitrogen, mg/-L N
BOD, mg/-t O
COD, mg/-t O
Sulfate, mg/-L SO4
Total Phosphate, mg/-t PO4
Chloride, mg/l Cl
Sodium, mg/-t- Na
Potassium, mg/-L K
Boron, mg/£ B
Iron, mg/£ Fe
Mission
3-18-68
5. 75
45, 070
172
44, 900
22, 800
1, 200
15, 600
9,680
0. 0
104
10, 900
76, 800
1, 190
0. 24
660
767
68
1.49
2, 820
Canyon Landfill
3-24-71
7.40
13, 629
220
13,409
8, 930
216
8, 714
8, 677
270
92.4
908
3, 042
19
0. 65
2, 355
1, 160
440
3. 76
4. 75
Such experiments as the foregoing support the conclusion previously
cited that leachate from well-designed fills is not a significant
problem.
The time required to produce leachate from a fill penetrated by rainfall
can be predicted by moisture-routing techniques (Remson, 1968). For
example, an 8-foot lift of refuse with 2 feet of earth cover will take
from one to 2-1/2 years to reach field capacity and produce leachate if
44 inches of rainfall is allowed to infiltrate and percolate into the fill.
2-110
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The nature of leachate reaching groundwater depends its passage
through soil systems. Reduction in BOD of leachate was observed to
be 95 percent during travel through 12 feet of soil (Emrich and Landon,
1969). The ability of aerobic soil systems to stabilize organic matter
is well known (McGauhey and Krone, 1967); consequently, an increase
in dissolved minerals is the effect on groundwater to be expected from
leachate infiltrating surface soils. Fills which produce leachate that is
not discharged to the soil surface soon develop an underlying anaerobic
zone of clogging. Leachate which passes through this zone of clogging
may be expected to be high in BOD, COD, and tastes and odors. These
quality factors may be little changed in the groundwater except by dilu-
tion until the groundwater outcrops or is withdrawn through a well and
becomes reseeded with aerobic organisms. In reality it makes little
difference whether a leaching landfill is above or in contact with the
groundwater because in either case there is no biologically active zone
to change the nature of the pollutants. However, if groundwater in con-
tact with refuse is the leaching medium, any rise and fall in the water
table may have a surging effect and so accelerate the pickup and mixing
of groundwater and leachate. In one field observation (Hassan, 1971) a
landfill partly inundated by groundwater was investigated. Well water
325 meters down gradient from the fill showed leachate effects in terms
of hardness, alkalinity, Ca, Mg, Na, K, and Cl. At a distance of 1,000
meters the effects were undetectable. Inasmuch as the fill was an old
one it might be concluded that the groundwater was not seriously
affected. However, similar studies in Germany revealed the presence
of leachate effects in groundwater 3, 000 meters away.
The nature of leachate can be expected to change as years go by.
Present trends toward greater use of garbage grinders can significantly
reduce the BOD of leachate. For example, Table 2-14 shows only 6
percent food wastes in Los Angeles, where household garbage grinders
2-111
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are common, as compared to the 15 percent national average.
Moreover, the increasing use of plastics increases the content of
inerts. Future use of refuse fiber for energy production could elimi-
nate most organic matter and increase the content of leachable ashes
in urban refuse.
In the case of industrial wastes disposed of by landfill on company
property, little is known of the nature and extent of leachate. Table
2-15 shows that non-combustible solids represent 75 percent and ashes
another 14 percent of the total. These data suggest that soluble miner-
als are the most common materials which might be leached from
industrial waste fills. In terms of groundwater pollution oil, process
sludges, and salt solutions from lagoons and pits are likely to be the
most significant industrial wastes.
Control Methods
In general, procedures for the control of leachate are those which
exclude water from the landfill, prevent leachate from percolating to
the groundwater, or collect leachate and subject it to biological treat-
ment. Obviously, the possible utilization of these three approaches is
maximum in the design phase of a landfill operation and minimal in
some types of existing landfills.
In existing situations the potential of a landfill to pollute groundwater
can be limited by such procedures as:
• Separating at the source wastes which are unacceptable in a
given landfill situation
• Controlling haulers by requiring permits and by enforcing
restrictions on materials for disposal
• Licensing private haulers of industrial wastes.
2-112
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In the case of a new projected landfill the control measures include:
• Select site to achieve both general regulations and specific
objectives. Typical of the general measures for siting
control are those of Los Angeles County which recognize
three classes of fills;
— Class I, which may accept all types of solid wastes by
reason of its geologic isolation from any contact with
the groundwater. This type of site is essentially an
impervious bowl, and hence is not common.
— Class II, which may accept the normal run of mixed
municipal solid refuse (no waste oils, or chemical
sludges).
— Class III, which may accept only inert earth-type
materials.
Specific siting involves evaluation of alternate locations by
hydrogeologists and engineers to determine such things as:
— Location and depth of ground-water in the vicinity.
— Importance of underlying groundwater as a resource,
both present and future.
— Nature of geology of the site.
— Feasibility of excluding both surface water and
groundwater from the finished fill.
• Design landfill to correct deficiencies of best available site:
— Use compacted earth fill to seal walls and bottom of
fill site. If the fill is above groundwater, as is most
commonly required, this will minimize the rate of
escape of leachate from the fill. If the fill is in ground-
water the movement of the groundwater into and out
of the fill will be minimized.
2-113
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- Provide underdrainage system to collect leachate
and deliver it to a sump.
- Drain sump to surface by a valved pipe or by a
vertical well into which a submersible pump
may be inserted, if necessary, to collect and
deliver leachate for biological treatment.
• Construct fill with purpose of keeping the minimum of refuse
surface exposed to rainfall, and the working surface and site
well drained. Use dike and fill technique to isolate fill from
unfilled area.
• Utilize water for dust control during construction in such
amounts that evaporation rather than infiltration is its fate.
• Divert surface water from the fill site during and after fill
construction by means of peripheral bypass drains.
• Compact and slope fill cover for good surface drainage;
vent gases through the fill cover with j-vents.
In new or existing landfills:
• Provide continuing maintenance of the graded finished fill
cover; fill in and regrade surface as shrinkage of the fill
causes cracks or depressions which might serve to
increase infiltration.
• Seed completed fill surface with a high transpiration cover
crop.
• Avoid over irrigation of surface plantings.
• Divert both surface and groundwater around fill site where
feasible.
2-114
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• Reduce the amount of putrescible solid waste by initiating
regional reclamation activities under a statewide
authority which features energy conversion of the organic
fraction of refuse.
In the case of existing landfills and dumps:
» Intercept polluted groundwater at the fill site by well points
in or near the fill area if the situation is serious.
• Initiate and implement statewide programs of waste
management which feature regional landfills, thus
replacing numerous small refuse dumps with landfills on
an economic scale, and so phasing out with time the
leachate contribution to groundwater.
Cf the foregoing control measures only those which are applicable to
new sanitary landfills have the potential to prevent or essentially to
eliminate the possibility of groundwater pollution by leachate. Siting,
constructing, operating, and maintaining fills are in this category of
control measures. Existing well-engineered landfills, although not
generally equipped with underdrains, are minimal in their effects upon
groundwater quality and hence of secondary importance in comparison
with dumps. Similarly old landfills may have contributed the major
portion of their leachate already and are now of secondary importance.
Reshaping the soil surface and maintaining surface drainage are mea-
ures which reduce the effect of leachate from existing fills. The over-
all effect of dumps may be lessened by a geographical distribution of
the volume of wastes they contain. Control measures such as well-
point interception reduce rather than prevent or eliminate leachate dis-
charges. Regionalization is a control measure which can reduce and
eventually phase out the leachate from existing dumps.
2-115
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Monitoring Procedures
In new fills, properly engineered and sealed off from underlying and
sidewall strata, the drainage system and a pumped well located in or
near the fill can be used both for inspection (monitoring) and for
control.
A system of three observation wells (Hughes, et al, 1968) is illustrated
in Table 2-19 along with the results of groundwater quality observations.
Table 2-19. Groundwater quality.
1
; Groundwater
Characteristic
Total Dissolved
j Solids
'; PH
COD
; Total Hardness
Sodium
i Chloride
0 -_(
Background
(mg/liter)
636
7. 2
20
570
30
18
/ x~\ X *i
*"> v >y
Fill
(mg/liter)
6712
6. 7
1863
4960
806
1710
>5 0
i
I
Monitor Well
(mg/liter) ]
1506
7. 3
71
820
316
248
It would be feasible to drill and gravel pack a sampling well in a
landfill, then seal its bottom and drill through to the groundwater
below. Portable submersible pumps could be used to pump these two
essentially concentric wells for sampling purposes. An alternative
might be to drill a pumped monitoring well downstream from the land-
fill or directly through the fill. Concentrations of TDS, hardness, and
chlorides could be measured and used to surmise the presence of
leachate, provided the discharge rate needed to produce a significant
-------
drawdown cone under the fill did not obscure the effect of leachate on
the groundwater quality.
In any event the best procedure is the use of control measures which
minimize the possibility of leaching of landfills and which, consequent-
ly, reduce the need to search for underground pollutants and to assess
their concentration in groundwater.
2-117
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References
1. Anderson, D. R. , and Callinan, J. P. , Gas Generation and
Movement in Landfills, paper (1969).
2. Anon., "Sanitary Landfills: The Latest Thinking, " Civil
Engineering, Vol. 43, No. 3, pp 69-71 (1973).
3. Bergman, R. D. , "Urgent Need to Recycle Solid Wastes?, " Civil
Engineering, Vol. 42, No. 9 (1972).
4. Bell, J. M. , "Characteristics of Municipal Refuse, " Proceedings
of National Conference on Solid Wastes Research, American
Public Works Association Research Foundation, Chicago (1963).
5. Burch, L. A. , "Solid Waste Disposal and Its Effect on Water
Quality, " Vector Views, Vol. 16, No. 11 (1969).
6. California State Water Pollution Board, Report on Investigation of
Leaching of a Sanitary Landfill, Publication No. 10, Sacramento,
California (1954).
7. Dair, Frank R. , "The Effect of Solid Waste Landfills on
Ground-water Quality, " Sixth Biennial Conference on Groundwater
Recharge, Development Management, University of California,
Berkeley (1967).
8. Emrich, G. H. , and Landon, R. A. , "Generation of Leachate from
Landfills and Its Subsurface Movement, " Annual Northeastern
Regional Anti-Pollution Conference, University of Rhode Island,
Kingston (1969*
9. Environmental Protection Agency, "A Citizen's Solid Waste
Management Project, " Mission 5000, EPA (1972).
10. Environmental Protection Agency, Comprehensive Studies of
Solid Waste Management, First and Second Annual Reports, US
Department of Public Health Service, Publication No. 2039,
Research Grant EC-00260, University of California (1970).
11. Environmental Protection Agency, Solid Wastes Disposal Study,
Vol. 1, Jefferson County, Kentucky; Institute of Industrial
Research, University of Louisville, US Department of Health,
Education, and Welfare, Bureau of Solid Waste Management
(1970).
2-118
-------
12. Golueke, C.G. , and McGauhey, P.H. , Comprehensive Studies of
Solid Waste Management, First Annual Report, SERL Report No.
67-7, Sanitary Engineering Research Laboratory, University of
California, Berkeley (1967).
13. Ham, R. K. , personal communication, University of Wisconsin
(1971).
14. Hassan, A. A. , "Effects of Sanitary Landfills on Quality of
Groundwater — General Background and Current Study, " Paper
presented at Los Angeles Forum on Solid Waste Management
(1971).
15. Hughes, G. M. , et al, Hydrogeology of Solid Waste Disposal Sites
in Northeastern Illinois, Progress Report D01-00006, US Depart-
ment of Health, Education, and Welfare (1968).
16. Kaiser, E. R. , "Chemical Analysis of Refuse Components,"
Proceedings 1966 Incinerator Conference, American Society of
Mechanical Engineers, New York, New York (1966).
17. Los Angeles County, Development of Construction on Use
Criteria for Sanitary Landfills, USPHS Grant No. D01-Ul-00046,
County of Los Angeles, California (1968).
18. Manufacturing Chemists Association, "Most Solid Wastes from
Chemical Processes Used as Landfill on Company Property, "
Currents (1967).
19. Meichtry, T. M , "Leachate Control Systems," Paper presented
at Los Angeles Forum on Solid Waste Management (1971).
20. Merz, R. C. , and Stone, R. , Progress Report on Study of
Percolation Through a Landfill, USPHS Research Grant SW 00028-
07 (1967).
21. McGauhey, P. H. , and Krone, R. B. , Soil Mantle as a Wastewater
Treatment System, Final Report, SERL Report No. 67-11, Sani-
tary Engineering Research Laboratory, University of California,
Berkeley (1967).
22. McGauhey, P. H. , and Winneberger, J. H. , Causes and Preven-
tion of Failure of Septic-Tank Percolation Systems, Tech. Studies
Report, FHA No. 533, Federal Housing Administration,
Washington, B.C. (1964).
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23. Niessen and Chansky (Arthur D. Little, Inc.), "The Nature of
Refuse, " Proceedings 1970 National Incinerator Conference,
American Society of Mechanical Engineers, New York (1970).
24. Qasim, S. R. , and Burchinall, J. C. , "Leaching from Simulated
Landfills, " Journal Water Pollution Control Fed. , Vol. 42, No.
3, pp 371-379 (1970).
25. Remson, I. A. , et al, "Water Movement in an Unsaturated
Sanitary Landfill, " Journal Sanitary Engineering Division,
American Society of Civil Engineers, pp 307-317 (1968).
26. Salvato, J. A. , et al, "Sanitary Landfill-Leaching, Prevention
and Control, " Journal Water Pollution Control Fed. (1971).
27. Saxon's River Conference, Evaluation of Sanitary Landfill Design
and Operational Practice, Engineering Foundation Conference
(1972).
28. Stolp, D. W. , personal cornrrrunication, V. A. M. , Holland (1972).
29. Sumner, J. C. , Controlled Tipping in Europe, Engineering
Foundation Conference, Department of the Environment, London
(1972).
30. US Public Health Service, Quad-City Solid Wastes Project - An
Interim Report, Junel, 1966 to May 31, 1967, USPHS,
Cincinnati (1968).
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SECTION III
INDIRECT DISPOSAL OF POLLUTANTS
SEWER LEAKAGE
Scope of the Problem
Gravity sewers above the groundwater table and pressure outfalls
either above or below that table are common elements of the domestic
sewerage system of organized communities. Seasonally, storm
sewers involving underground conduits and lined and unlined open
channels carry runoff from paved and unpaved land surfaces. Essen-
tially all of these conduits are sited to accomplish drainage objectives.
Many major sewer systems had their beginnings at least a century ago
and some of the early sectors of these systems are still in use. Over
this long period, construction materials and methods have changed
profoundly as the total length of sewers grew to tens of thousands of
miles. Joints in many of the gravity sewer systems carrying domestic
sewage number from 1, 000 to 2, 000 per mile. Joining materials have
ranged through the years from cement mortar to asphaltic and similar
special compounds and to plastic O-rings and heat-shrinkage joint
covers.
Causal Factors
The potential of a municipal sewage system to contaminate groundwater
is both varied and variable. Conceptually, a sewer is intended to be
water-tight and thus to present no hazard to groundwater except when
temporarily disrupted by accident. In reality, however, leakage is a
common occurrence, especially from older sewers. Leakage in gravity
sewers may result from causes such as:
• Poor workmanship, especially at the time cement mortar was
applied by hand as a joining material
• Cracked or defective pipe sections incorporated in the sewer
3-1
-------
• Breakage of pipe and joining material by tree roots
penetrating or heaving the sewer line
• Displacement or rupture of pipeline by superimposed
loads, heavy equipment, or earthfill on pipe laid on a poor
foundation
• Rupture of pipe joints or pipe sections by slippage of soil
in hilly topography
• Fracture and displacement of pipe by seismic activity; eg,
a sewerage system in California still suffers from frac-
tures caused by an earthquake in 1909
• Loss of foundation support due to underground washout
• Poorly constructed manholes or shearing of pipe at man-
holes due to differential settlement
• Infiltration surcharging the system and causing sewage to
back up into abandoned sewer laterals.
Environmental Consequences
Except at times of heavy infiltration during storms, which may
surcharge a system, the piezometric pressure inside a gravity sewer
laid above groundwater is small. The static head may vary from a
maximum equal to the pipe diameter to a minimum of perhaps 20 per-
cent of that diameter. Consequently, the rate of leakage accompanying
several of the cited failures is quite small. In fact, some small leaks
become stopped through clogging of the opening by suspended solids.
Major fractures may release an appreciable amount of sewage which
moves along the pipe foundation as the soil clogs, causing the trench
locally to function like the percolation system of a septic tank.
Materials escaping from a sewer via leakage is raw sewage, which
may be actively decomposing, together with such industrial waste
3-2
-------
chemicals as may be present in the sewer. Thus, if a sewer is deep
underground and close to the groundwater, pollutants may be released
below the biologically active zone of the soil and so introduce into the
receiving groundwater BOD and COD as well as chlorides and unstable
organics productive of tastes and odors. Because this tendency is
partly offset by the clogging of soils under anaerobic conditions, the
true effect of sewer leakage on groundwater quality is probably far less
than the theoretical potential.
If a fractured sewer is below the groundwater table, infiltration rather
than leakage is the result. If infiltration is seasonal and leakage occurs
part of the year, the effect of the intermittent flow may be to unclog the
system and so maintain a higher seasonal leakage rate than that of
year-round leakage.
Pressured outfall sewers are normally made of cast iron, steel,
transite, or concrete pipe. Except in very large diameters they have
fewer joints per mile than gravity sewers, and the joining is less likely
to be of poor quality or so readily ruptured. Because of superior con-
struction and engineering attention, the outfall sewer is not often a
threat to groundwater quality. Due to the internal pressure when leak-
age does occur, it is normally outward regardless of whether the pipe
is above or below the water table. Small openings may clog but most
commonly sewage is injected into soil or groundwater directly. It may
appear on the surface of the soil or outcrop on a hillside where it is
easily detected by sight and odor.
The effect of storm drains is generally to hasten the flow of surface
water to a surface stream. Therefore, it is likely to have less poten-
tial than uncontrolled surface runoff to spread the oils and soluble mat-
ter from streets, fertilized land, and pesticide-treated gardens over
infiltrative surfaces feeding the groundwater.
3-3
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Looking to the future, it seems certain that sewer leakage will be less
of a hazard to groundwater than at present, even though the extent of
sewer systems is certain to increase to accommodate the growth and
urbanization of population. The principal reasons are improved con-
struction and maintenance practices:
• Both new sewers and replaced old lines are laid with joining
materials which are water-tight and also permit some
change in pipe alignment without fracturing
• Better construction methods are practiced by contractors
• More rigid specifications and better inspection charac-
terize the larger units of government now responsible for
sewerage
• Equipment for photographing or televising the interior of a
pipeline is available and increasingly used to locate leaks
and fractures in a sewer system
• Municipal public works departments, using their own per-
sonal or private contractors, are increasingly and system-
atically surveying the condition of sewers within their
jurisdictions in a "search and destroy" program of sewer
repair and maintenance
• Sewer maintenance has become a special division of public
works departments, and both the Water Pollution Control
Federation and its member societies conduct annual short
courses and training programs in the technology of
maintaining sewers.
Control Methods
Procedures for controlling the potential of sewer leakage to degrade
groundwaters are implicit in the improved practices listed above. The
3-4
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sewerage system of a large community is an infinite point system of
possible leaks. Moreover, the system is underground and hence not
subject to control by surface observation and repair. Therefore, the
most productive control program has the following features:
• A public policy of maximum protection of groundwater as a
part of an overall concern for resource conservation
• An organized and identified responsibility for sewer con-
struction and maintenance in the community
• Formulation and modernization of codes and specifications
for sewer construction as a state rather than a city
responsibility, together with appropriate inspection
procedures
• A program of internal and external inspection of existing
sewers at five-year intervals to detect and repair major
leaks or to replace unrepairable sectors of the sewer
system
• Emphasis on training of sewer maintenance personnel
• Exclusion from discharge to municipal sewers of any
materials found to be irretrievably hazardous to ground-
water.
Monitoring Procedures
As in the case of lagoons, basins, and pits, monitoring of groundwater
quality in relation to sewer leakage is best accomplished by a program
of collection and evaluation of groundwater data in each metropolitan
area. Similarly, surveillance of the control procedures should be
maintained so as to prevent and to correct leakage.
3-5
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TANK AND PIPELINE LEAKAGE
Scope of the Problem
In the United States underground storage and transmission of a wide
variety of fuels and chemicals is a common practice for commercial,
industrial, and individual uses. Unfortunately, the pipes and tanks are
subject to structural failures from a wide variety of causes and the sub-
sequent leakage then becomes a source of contamination to local ground-
waters. European countries also have experienced these problems;
their technical literature is well worth consulting.
This section describes the nature and occurrence of tank and pipeline
leakage and summarizes the practices that have been found effective in
the control and abatement of groundwater pollution. Emphasis in this
section is on petroleum products because they are the majority of
materials stored or transmitted in subsurface excavations.
Leakage of petroleum and petroleum products from underground pipe-
lines and tanks may be much more pervasive than is generally realized.
This is particularly true for small installations such as home fuel oil
tanks and gasoline stations, where installation, inspection, and main-
tenance standards may be low. In Maryland, where standardized investi-
gative procedures have been adopted, some 60 instances of groundwater
pollution were reported in a single year from gasoline stations (Matis,
1971). In northern Europe, where most homes are heated by oil stored
in subsurface tanks, oil pollution has become the major threat to ground-
water quality (Todd, 1973).
Radioactive Wastes
Tanks of solid short-lived radioactive wastes often are buried in under-
ground pits, primarily as a means of storing them in a shielding medium
while the radioactivity decays. Five sites are used in the United States,
operating under license and regulated by the states in which they are
3-6
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located: Richland, Washington; Beatty, Nevada; Sheffield, Illinois;
West Valley, New York; and Moorehead, Kentucky (Atomic Energy
Commission, 1969). Under state regulations, the sites are designed
and operated so that no leakage should occur; to assure that no leakage
is occurring, the states require and perform monitoring of surface
water and groundwater in the vicinity of the sites as well as from sumps
in the backfilled pits.
History
Underground tanks and pipes have been used for storage and transmis-
sion of liquids whenever the need for space or protection so dictated.
In the United States the use of underground tanks and pipes has been
most heavy in the petroleum industry. Here their use has expanded
with the industry to the point where pipelines are now the major mode
of transportation for liquids and gases within the continental United
States.
Traditionally, pipelines and storage tanks have been buried only when
the cost of burial did not exceed the cost of the area they would other-
wise occupy, or the cost of the potential damage done to them by
weather, vandalism, etc. The present and increasing emphasis on the
aesthetic value of burying utilities and other commercial or industrial
structures will undoubtedly increase the number of tanks and pipes that
will be placed in excavations. Because pipelines are an economical
means of shipping, there is an increasing trend toward developing
methods for pipelining solids such as coal or ores by powdering the
solids and mixing them with -water or oil to produce a pumpable slurry.
Leakage in the United States
TANKS. Underground storage tanks are used in the United States by
industries, by commercial establishments, and by individual residences.
Industrial use is predominantly for fuels, but a wide range of other
3-7
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chemicals are also stored in tanks. Commercial businesses and indi-
vidual homeowners use underground storage almost exclusively for fuel.
The most numerous underground storage tanks are those used by gasoline
stations and for fuel oil at residences. These small tanks are usually
coated -with a protective paint or corrosion resistant material, but they
are frequently subject to corrosion-induced leakage. The primary
problem associated with such tanks is the fact that their installation and
use are not usually well regulated. If any regulation exists concerning
such tanks, in most cases it is a local regulation requiring that tank
construction and installation be satisfactory, but it is rare that any
followup or periodic checks are required to determine whether or not
leaks have developed. Because such tanks are small and comparatively
inexpensive, cathodic protection is not required even when the tanks
are in clay soils, which are known to promote galvanic action.
PIPELINES. Pipelines are used in three forms: for transportation,
for collection, and for distribution.
Transportation pipelines are used for a wide number of chemicals such
as oil, gas, ammonia, coal, and sulfur. Their heaviest use is for the
transportation of petroleum products, natural gas, and water, in that
order. The list of commodities lost by accidents during one year from
liquid interstate pipelines is shown in Table 3-1.
Many industries employ underground collection pipelines to move pro-
cess fluids and wastes in-plant or for storage or shipment. In oil fields,
collection pipelines are used to bring crude oil from wells to tanks for
separation of brines, storage, and shipment.
The only pipelines for which any program of leak prevention and any
requirements for decontamination exist are the transportation pipelines,
and all of these are not covered. All interstate transportation pipelines
and some intrastate pipelines are regulated; on collection and distribution
3-1
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Table 3-1. Summary of interstate liquid pipeline
accidents for 1971 (Office of Pipeline
Safety, 1972).
Commodity
Crude Oil
Gasoline
L. P. G.
Fuel Oil
Diesel Fuel
Condensate
Jet Fuel
Natural Gasoline
Anhydrous Ammonia
Kerosene
Alkylate
Total
No. of
Accidents
172
51
39
21
5
5
4
4
3
2
2
308
% of
Total
55.9
16.6
12.7
6.8
1.6
1.6
1. 3
1.3
1.0
.6
.6
100.0
Loss
(Barrels)
115,760
42, 001
39,887
13,724
6. 953
3,658
2,236
8,743
9,810
700
1, 585
245,057
% of
Total
47.2
17. 1
16. 3
5. 6
2.8
1. 5
.9
3. 6
4. 0
. 3
. 7
100. 0
pipelines there is no regulation other than that of the initial installation.
The purpose and intent of the regulations that exist are for preventing
the escape of combustible, explosive, or toxic chemicals. Prevention
of groundwater pollution has not heretofore been considered.
Because interstate pipelines are a major means of transportation, they
are regulated by federal government agencies in the Department of
Transportation. Furthermore, because leaks of petroleum products
can produce a fire or explosion hazard, these regulated pipelines have
been required, for the past 5 years, to report leaks and spills. An
analysis of these reports (Office of Hazardous Materials, 1969; Office
of Pipeline Safety, 1971; 1972) has been made and is summarized in
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Table 3-2. It should be noted that the quantities reported represent only
leakage associated with interstate carrier systems. This means that
local distribution systems, gas stations, residential storages, and even
relatively large intrastate carriers are not included. Therefore, it
must be assumed that the leakage reported covers perhaps 10 to 25 per-
cent of the total leakage in the country.
Environmental Consequences
Pipeline and tank leakage into the soil can have several environmental
consequences, depending upon the chemical leaked. Oils and petroleum
products in even trace quantities will render potable water objectionable
because of taste, odor, and effects on vegetation growth.
In sufficiently high concentrations the vapors of lighter fractions of
petroleum products, liquified petroleum gas, and natural gas can seep
into basements, excavations, tunnels, and other underground structures.
These vapors mixed with the air in the cavity constitute a severe explo-
sion or fire hazard in the presence of open flame or sparks.
Table 3-2. Range of annual pipeline leak
losses reported on DoT Form
7000-1 for the period 1968
through 1971.
Number of accidents -- 300 to 500
Number of barrels lost -- 250, 000 to 500, 000
Value of property damage -- $650, 000 to $1, 300, 000
Number of deaths -- 1 to 11
Number of injuries -- 8 to 32
Major cause -- Corrosion
Major commodity lost -- Crude oil
3-10
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Chemicals such as ammonia and other agricultural or industrial chem-
icals can have toxic properties. For example, ammonia •will add to the
nitrification of groundwater, while acids can change the pH of ground-
water which, in turn, will accelerate the solution of soil solids and heavy
metals.
The leakage of water can produce undesirable effects if the dissolved
solids in the water introduce objectionable hardness or if the water is a
brine.
Causal Factors
The annual reports of the Office of Pipeline Safety summarize the causes
of leakage of interstate pipelines. This list appears to be representative
of the causes of leaks for all pipelines and tanks.
Table 3-3 is extracted from Office of Pipeline Safety (1972) to show the
relative frequency of causes. Other causes that have been reported in
other years but did not occur in 1971 were flood and surge of fluid in the
pipeline. Examination of the table indicates that the major cause of
leakage is corrosion, which attacks the lines both externally and inter-
nally. The second greatest cause can be found by aggregating those
related to pipeline component, equipment, personnel failure, or mal-
function. The third greatest cause is line rupture as the result of attack
by earth moving equipment.
The remaining small number of causes include vandalism (usually bullet
holes in exposed sections of pipe, tanks or valves) and acts of God such
as cold weather, lightning, floods, earthquakes, forest fires, etc. In
general, pipelines are routed to avoid areas with a history of such acts
of God or are structurally designed to withstand such problems as cold
weather or earthquakes.
3-11
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Table 3-3. Frequency of causes of pipeline leaks
in 1971 (Office of Pipeline Safety,
1972).
Cause
Corrosion- external
Equipment rupturing line
Defective pipe seam
Corrosion- internal
Incorrect operation by carrier personnel
Miscellaneous
Ruptured or leaking gasket
Ruptured or leaking seal
Defective repair weld
Unknown
Ruptured leaking or malfunction of valve
Rupture of previously damaged pipe
Malfunction of control or relief equipment
Cold weather
Defective girth weld
Threads stripped or broken
Pump packing failure
Vandalism
Lightning
TOTAL
Number
102
67
31
22
22
12
7
6
6
6
5
4
3
3
3
3
2
2
2
308
Percent
33. 1
21.8
10. 1
7. 1
7. 1
3.8
2. 3
2. 0
2.0
2. 0
1. 6
1. 3
1. 0
1.0
1. 0
1.0
0.6
0.6
0. 6
100. 0
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Pollution Movement
A leak into an underground excavation can behave in several "ways,
depending on the characteristics of the soil and the depth below the leak
of the saturated zone. The statements below apply not only to oil but
also to all liquid pollutants emanating from underground tanks and pipe-
lines.
If the leak is from a tank of limited horizontal extent or from a pipeline
in relatively permeable soil, the liquid will remain in the vicinity of the
leak and move downward through the soil under the influence of gravity.
On the other hand, if the leak is from a pipeline in relative impermeable
soil, the leaked liquid will tend to remain in the trench. In a sloping
trench in impermeable soil, the leaked fluid will tend to move through
the backfill in the trench along the outside of the pipe in the direction of
the slope.
As leaked liquid moves downward through the soil under the influence of
gravity, it will coat the soil particles as it advances. This process
removes some fluid from the downward moving body. If the quantity of
leaked liquid is small enough, it may be exhausted to immobility by this
process as shown in Figure 3-1. However, the leaked liquid will not
remain immobilized. Subsequent rainfall will wash the pollutant from
the soil particles and carry it further downward until eventually it -will
reach the saturated zone.
If the leakage is large enough to reach the saturated zone before exhaus-
tion, its path of movement •will depend upon the density and viscosity of
the fluid and whether it is miscible -with water. Miscible liquids •will
tend to mix and thus to dilute slowly with distance and time. Subsequent
rainfall will tend to displace oil or other low density fluids lying on the
water table, producing a mixture that •will extend into the saturated zone.
Once in the saturated zone, a pollutant will move downstream in the direc
tion of the water table gradient as shown in Figure 3-2.
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LA*D SURFACE
° o • 0°. '.v^^-viviffr^r'." «e c : •
n &° a a _ QQ Q_. A a ^_ a ^ * - ^. t
A-HIGHLY PERMEABLE, HOMOGENEOUS SOIL
B- LESS PERMEABLE, HOMOGENEOUS SOIL
C - STRATIFIED SOIL WITH VARYING PERMEABILITY
Figure 3-1. Generalized shapes of spreading cones
of oil at immobile saturation (Comm.
on Environmental Affairs, 1972).
-------
GROUND WATER CONTAMINATED BY SOLUBLE COMPONENTS.
FLUID OIL FLOATING ON WATER TABLE.
RESIDUAL SATURATION
Figure 3-2. Movement of oil away from a spill area under
the influence of a water table gradient (Comm.
on Environmental Affairs, 1972).
-------
Figure 3-3 shows a plan view of an actual situation involving a large
gasoline spill and indicates how the leakage apparently concentrated in
a depression in the water table created by pumping wells.
It is quite possible for leaked liquids to move laterally for great dis-
tances above the saturated zone. If a spill is large enough or if a leak
continues long enough, the fluid can migrate along impermeable layers
above the water table as shown in Figure 3-4. The same can happen
along a pipeline, as described earlier, until it reaches a permeable
region where it can penetrate downward.
* STRONG TASTE
AND ODOR
Figure 3-3. Area contaminated by subsurface
gasoline leakage and groundwater
contours in the vicinity of Forest
Lawn Cemetery, Los Angeles
County, as of 1971 (Williams and
Wilder, 1971).
3-16
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AREA OF SPILL
Figure 3-4. Illustration of the possible migration
of an oil spillage along an impermeable
layer, to an outcrop, and hence to a
second spill location (Comm. on Envir-
onmental Affairs, 197Z).
-------
It should be noted that most chemicals do not move with the velocity of
the groundwater. Because of the effects of sorption, varying miscibility
and solubility with water, and varying chemical activity with the soils,
chemicals usually migrate through the soil in the direction of the ground-
water flow but at a slower rate (Comrn. on Environmental Affairs, 1972).
Control Methods
At the present time, most of the research and development work on
methods for controlling and abating the contamination of groundwater by
leakage from tanks and pipelines in underground excavations has been
concerned with reducing fire, explosion, and toxicity hazards. Although
it would appear that this work is not often aimed toward abating pollution
of groundwater, it may be applicable if judiciously applied. Further,
many references that describe methods for handling hazardous materials
can also be applied for handling leakage materials such as sewage,
brines, and agricultural and industrial chemicals not considered to be
hazardous.
PREVENTION. Primary control methods emphasize three types of leak
prevention:
• Corrosion-preventing coatings such as tar or plastic are
used on the outside of tanks and pipelines.
• Cathodic protection is used to minimize corrosion resulting
from galvanic action (Dept. of Transportation, 1969, 1970a).
• Internal fibreglass linings, which do not deteriorate, are
coming into use for small tanks such as those used for
gasoline storage (Matis, 1971).
CONTAINMENT. Storage sites can be designed to contain leaked liquids
so that they can be trapped and removed before they get into the soil.
These methods are almost exclusively applied to tanks. Lined excavations
3-18
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are sometimes used to enclose a subsurface tank with an impermeable
material such as clay, tar, or sealed concrete. These are analogous
to the dikes used for containment in oil-tank farms.
Another method has been used in Switzerland (Todd, 1973) for containing
liquids that are lighter than water, such as oil. An underground dam is
built around the tank. The dam is designed to penetrate the water table
to such a depth that the full volume of the tank could leak into the space
inside the darn, and the bottom of the pool of leaked fluid would be well
above the bottom of the dam.
In pipelines, containment can be accomplished by use of automatic shut-
off valves inserted in the pipe at intervals. These valves are designed
to close off any section of pipe where a significant drop in line pressure
occurs. This method, like containment devices for tanks, tends to limit
the spread and the volume of the leak and thereby permit easier cleanup.
At the present time this form of protection is required on interstate
pipelines but not on most small collection and distribution systems.
ABATEMENT BY REMOVAL OF SOIL. If a leak is discovered and is
accessible soon after it occurs, perhaps the best method for preventing
groundwater contamination is removal of the soil soaked -with the leakage.
It is important that this method be applied before rainfall occurs in the
region. Normally, -without the flushing action of rainfall, liquids move
downward very slowly under the influence of gravity.
Figure 3-5 (Todd, 1973) indicates that from several hours up to a day
or more may be available before leaked liquids reach depths beyond those
that would be reasonable for normal earth removal. This slow migration
downward is a characteristic not only of leaks small enough that they
will be exhausted to immobility before they reach the saturated zone but
also of leaks large enough to eventually reach the saturated zone. Thus,
3-19
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Oil Saturation in %
i-
2-
3-
4-
9-
10
i
20
30
40
50
/
Initial
IO hours
/ 23 hours
S(0) - 50 % d « 0,59 m
SOO) * 8,5% d • 3,45 m
S(23) • 6,1% d • 4,80m
S(72» - 4,6% d • 6,40m
/72 hours
7-
Figure 3-5. Experimental results from Switzerland
on the distribution of oil in soil as a
function of time (Todd, 1973).
in dealing with the large leaks that are associated with a catastrophic
failure, such as a tank or pipe rupture, it is important to initiate cleanup
procedures as rapidly as possible.
After the soil has been removed, the problem of how to dispose of it must
be addressed. The most suitable method for handling biodegradable
materials, such as oil, and many agricultural chemicals such as ammonia,
3-20
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is to spread the contaminated soil in a thin layer, 20 centimeters or less
in thickness, and permit the natural aerobic soil bacteria to degrade it.
This is usually accomplished within six months. If the liquid is not bio-
degradable, the soil must be removed to an appropriate industrial waste
treatment plant and processed as an industrial waste.
It should be noted that earth removal can be an extensive operation requir-
ing more than simply digging a hole with a bulldozer and hauling the soil
away in a truck. In at least one case in an urban area (Geraghty, 1961),
such earth removal involved the demolishing of buildings and excavation
of an area of approximately the size of a city block.
ABATEMENT BY PUMPING OR DITCHING. In cases where the pollutant
has reached the water table but has not yet moved a significant distance
from the leakage site, a removal well can be used. This method works
best for water -soluble chemicals and for oils that float on the water
table; however, it can be expensive and time consuming. With respect
to soluble chemicals, the effect of pumping will be to reverse the normal
migration or flow away from the site of the leak; with respect to oil, the
drawdown cone that the well produces will trap the oil. In the case of
oil, two pumping locations are often used — a deep pump inlet to maintain
the drawdown cone and a skimming pump with its inlet floating on the
surface to remove the oils (Figure 3-6).
If the pollutant has moved so far downstream that recapture by use of a
drawdown cone is infeasible, a ditch placed across the contaminated
plume can be used to capture the pollutant. Figures 3-7 and 3-8 illustrate
this method.
When the water table is far below the surface of the ground, a row of
pumping wells may be required. Placed across the contaminated plume,
their drawdown cones will merge, producing a trench in the water table.
The contaminant cannot escape from the depression and with time will
3-21
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Figure 3-6. Swedish two-pump method
for removal of oil pollution
from a well (Todd, 1973).
3-22
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A1
LINE OF SECTION
FIG. 2-B
WATER MOVEMENT
PLAN VIEW
CROSS SECTION
Figure 3-7. Oil moving with shallow groundwater is inter-
cepted by a ditch constructed across migration
path (Comm. on Environmental Affairs, 1972).
3-23
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SUPPORT
H00\
TO SUCTION
POWER
SUPPLY
A FLOATATION DEVICE MAY BE SUBSTITUTED
FOR THE HANDLING CABLE OR ROD.
TO SUCTION PUMP
Figure 3-8. Three systems for skimming oil from a
•water surface in ditches or wells (Comm.
on Environmental Affairs, 1972).
3-24
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gradually be removed by the wells. After the contaminated water is
removed, it must be processed as an industrial wastewater before dis-
posal to a sewage system or return to the aquifer. The appropriate
technique will depend upon the nature of the pollutant and upon available
wastewater treatment facilities.
ABATEMENT BY BIODEGRADATION. A new method currently under
investigation is that of subsurface biodegradation. Many chemicals such
as ammonia and petroleum products are biodegradable by aerobic bac-
teria, but below the surface air transfer is slow and the aerobic bacteria
tend to consume the oxygen. At the present time research is being
conducted to identify anaerobic bacteria that would also be capable of
such biodegradation (McKee, et al. , 1972).
ABATEMENT BY CHEMICAL, ACTION. The use of chemical reagents or
pH changes has been suggested to cause precipitation of pollutants or
reactions with the soil to simply immobilize them. So far as is known
no experimental results are available. Further research on such methods
is required.
Monitoring Procedures
In general the monitoring required for the detection of leaks from tanks
and pipelines in excavations is in proportion to the quantity of chemicals
handled.
At the level of the household fuel storage tank, gasoline station storage
tank, and local collection or distribution system, local monitoring is
probably not economically feasible. If local governments regulate such
operations at all, they do so by ordinances and codes specifying the
materials and methods of installation. The most frequent occurrence of
leaks from underground pipes and tanks is from these small systems.
Commonly, monitoring for such leaks is by "discovery, " when a nearby
owner of a water well discovers that his well is contaminated. Other
3-25
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examples occur when an owner or operator discovers that the chemical
is disappearing from his tank faster than he is using it, or during the
rainy season when the water table rises above the level of a leak in a
tank so that the owner or operator discovers that the tank is supplying
water (Gilmore, 1973).
Monitoring methods and procedures for interstate carriers are under the
control of the Office of Pipeline Safety. To assure that interstate carrier
monitoring and pipeline operation are being done satisfactorily, the
Office of Pipeline Safety requires detailed reports of all leakages in next
excess of 50 barrels of commodities from initiation of the leak to the
time of cessation (Department of Transportation, 1969; Office of the
Secretary of Transportation, 1970).
Monitoring procedures described below have been developed and imple-
mented by interstate carriers, but they can be applied to any underground
tank or pipeline.
Pipelines contain pressure-monitoring devices that automatically close
valves to isolate a section of pipe whenever a significant pressure loss
occurs (Dept. of Transportation, 1969; 1970). Regular checking of pipe-
lines and tanks is accomplished by throughput monitoring, periodic
inspection, and periodic pressure testing (Dept. of Transportation, 1970a;
Office of the Secretary of Transportation, 1971; 1972). In all of these
monitoring procedures emphasis has been on hazard and on economics;
in general, if the leak is so small or so located that it constitutes no
hazard (as defined by the Office of Pipeline Safety) and the costs of repair-
ing the leaks are greater than the loss incurred by the leakage, no attempt
will be made to detect, locate, or repair the leak.
THROUGHPUT MONITORING. Throughput monitoring compares input
and output. This method will detect large leakage rates, but small rates,
comparable to the fluctuations in difference between the input and output
3-26
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measurements resulting from temperature changes, inaccuracies in the
measuring instruments, etc. , -will go undetected. Improved instrumen-
tation might permit the detection of such leaks, but usually they are
detected by periodic inspections and pressure tests.
PERIODIC INSPECTION. Periodic inspection includes a visit to the site
and at least a visual inspection. Often, if volatile chemicals are involved,
a length of pipe is inserted into the soil and air samples are drawn
through portable gas detectors. The periodic inspection of pipelines
usually takes the form of a patrol on foot, by truck, or from aircraft.
In all cases the dominant method of detection is visual. In addition to
seeking evidence of leaks in the vicinity of the pipelines, inspectors are
usually adept at identifying leaks by the effects that the chemicals have
on adjoining vegetation.
For tanks in lined excavations, liquid level sensors or vapor sensors
(for volatile fluids) can be placed in the space between the lining of the
excavation and the tank. These are connected to an alarm located where
personnel are on duty.
PRESSURE TESTS. Pressure tests are usually made on both pipelines
and tanks after repairs and periodically whenever corrosion may be a
problem. A tank or a section of pipeline is filled and pressurized, and
the pressure monitored. Allowance is made for temperature change and
expansion under pressure, and the degree of tightness is determined.
The normal pressure-test duration is 24 hours. A report must be filed
with the operator and the Office of Pipeline Safety.
This type of test is more sensitive than throughput monitoring and periodic
inspection, but because of the potential variation of many parameters
affecting the pressure, small persistent leaks may go undetected and
tests may prove inconclusive. An example of the ambiguity of such a
test resulted at Forest Lawn Cemetery in Los Angeles County (Williams
3-27
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and Wilder, 1971). A pipeline near the cemetery was suspected as the
source of gasoline leakage, shown in Figure 3-3. It was pressure tested,
but some experts said that the results indicated that the pipe was tight,
while others felt that the results indicated a small leak. As of 1972,
50, 000 gallons of gasoline had been recovered at this site, and it is esti-
mated that the total spill amounted to 250, 000 gallons.
MONITORING SOLID SHORTLIVED RADIOACTIVE WASTES. The mon-
itoring methods used for tanks of solid shortlived wastes buried in pits
include sampling from sumps, wells, and surface water. Laboratory
analyses are made for beta and gamma activity and tritium content. In
practice, the methods are similar to those for monitoring leachates from
sanitary landfills.
3-28
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References
1. Atomic Energy Commission, "Category VIII - Services, " The
Nuclear Industry, pp. 251-268 (1969).
2. Bureau of Surface Transportation Safety, A Systematic Approach
to Pipeline Safety, National Transportation Safety Board, Wash-
ington, D. C. (1972).
3. Committee on Environmental Affairs, The Migration of Petroleum
Products in Soil and Ground Water—Principles and Countermea-
sures, Publ. no. 4149, Amer. Petroleum Inst. , Washington,
D. C. , 36 pp. (1972).
4. Department of Transportation, "Title 49 - Transportation, "
Federal Register, v. 34, no. 191, Washington, B.C., 4 October
(1969).
5. Department of Transportation, "Part 195 -- Transportation of
Liquids by Pipeline, " Federal Register, v. 35, no. 62, Washington,
D. C. , 31 March (1970).
6. Department of Transportation, "Title 49 -- Transportation,"
Federal Register, v. 35, no. 218, Washington, D. C. , 7 November
(1970a).
7. Geraghty, J. J. , "Movements of Contaminants," Water Well Jour. ,
v. 16, October (1961).
8. Gilmore, D. , Personal Communication, March (1973).
9. Hepple, P. (Ed. ), The Joint Problems of the Oil and Water Industries,
Proc. of a Symposium Held at the Hotel Metropole, Brighton, 18-20
January 1967, The Institute of Petroleum, Longon (1967).
10. Jones, W. M. C. , "Prevention of Water Pollution from Oil Pipelines, "
Water Pollution by Oil, The Institute of Petroleum, London,
England (1971).
11. Laska, L. , "Water Pollution Control in Alaska, " Water, Air, and
Soil Pollution, D. Reidel Publishing Co. , Dordrecht-Holland,
pp. 415-432 (1972).
12. Matis, J. R. , "Petroleum Contamination of Groundwater in Maryland, "
Ground Water, v. 9, no. 6, pp. 57-61 (1971).
3-29
-------
13. McKee, J. E. „ et al. , "Gasoline in Groundwater, " Jour. Water
Pollution Control Federation, v. 44, pp. 293-302 (1972).
14. Office of Hazardous Materials, Summary of Liquid Pipeline Acci-
dents Reported on DoT Form 7000-1 from January 1, 1968 through
December 31, 1968, Dept. of Transportation, Washington, D. C.
(1969).
15. Office of Pipeline Safety, Summary of Liquid Pipeline Accidents
Reported on DoT Form 7000-1 from January 1, 1970 through
December 31, 1970, Dept. of Transportation, Washington, D. C.
(1971).
16. Office of Pipeline Safety, Summary of Liquid Pipeline Accidents
Reported on DoT Form 7000-1 from January 1, 1971 through
December 31, 1971, Dept. of Transportation, Washington, D. C.
(1972).
17. Office of the Secretary of Transportation, "Title 49 Transporta-
tion, " Federal Register, v. 35, no. 5, Washington, D. C. , 8 Janu-
ary (1970).
18. Office of the Secretary of Transportation, "Title 49 - Transporta-
tion, " Fede_ral_^e_g_is_ter, v. 36, no. 86, Washington, D. C. , 4 April
(1971).
19. Office of the Secretary of Transportation, "Title 49 Transporta-
tion, " F£der_al_Regj1£ter, v. 37, no. 180, Washington, D. C. ,
15 September (1972).
20. Todd, D. K. , Groundwater Pollution in Europe — A Conference
Summary, GE73TMP-1, General Electric Co., Santa Barbara,
Calif., 79 pp. (1973).
21. Toms, R. G. , "Prevention of Oil Pollution from Minor Users, "
Water Pollution by Oil, The Institute of Petroleum, London,
England (1971).
22. Williams, D. E. , and Wilder, D. G. , "Gasoline Pollution of a
Groundwater Reservoir—a Case History," Ground Water, v. 9,
no. 6, pp. 50-56 (1971).
23. Wood, L. A. , "Groundwater Degradation —Causes and Cures,"
Groundwater Quality and Treatment, Proc. of the 14th Water Quality
Conference, Univ. of Illinois, College of Engineering, Urbana-
Champaign, pp. 19-25 (1972).
3-30
-------
SURFACE WATERS
Scope of the Problem
Pollution by flow from surface water to groundwater is known to be taking
place in many parts of the country (Fuhriman and Barton, 1971), and
undoubtedly it is occurring in many other places as yet undetected.
Water applied during irrigation and water that temporarily covers the
surface of the land during floods are common ways in which contaminants
can enter the soil to pass downward into aquifers. Less widely appreci-
ated is the fact that surface waters in open bodies such as rivers and
lakes can be induced to enter shallow aquifers where groundwater levels
are lower than surface-water levels. Pumping from shallow wells near
a stream, as shown in Figure 3-9, and infiltration from flash runoff in
normally dry stream channels are two examples.
Surface runoff in urban areas contains a variety of pollutants; the infil-
tration and percolation of this water causes gradual local increases in
dissolved constituents in groundwater. The kinds of pollutants that can
enter aquifers through the mechanism of flow from surface to ground-
water include virtually the entire spectrum of inorganic and organic
compounds as well as bacteria and viruses.
The reverse problem, that of groundwater polluting surface -water, has
received relatively little attention. Invariably, flowing groundwater
discharges into a surface water body unless it is intercepted by pumping
wells. A large fraction of all streamflow is derived from drainage of
groundwater. Thus, long-term degradation of surface water can be
anticipated in areas where groundwater pollution continues to exist.
Environmental Consequences
Any pollutants entering the groundwater from surface-water sources
will gradually disperse with movement underground and may ultimately
affect the quality of a relatively large volume of groundwater in
3-31
-------
PUMPED
WELL
Figure 3-9. Diagram showing how contaminated -water is
induced to flow from a surface source to a
pumped well. Arrows show the direction of
groundwater flow (after Deutsch, 1963).
comparison to that initially affected. In general, dissolved solids move
farthest -with the groundwater and form a plume which may extend thou-
sands of feet downstream from a point source of pollution.
Nature of the Pollutants
Stormwater runoff exhibits a wide range of organic, bacteriological, and
chloride contents, as shown in the examples given in Table 3-4. Not
shown are other substances such as nitrate, lead, other heavy metals,
pesticides, and other organic compounds that have been reported in
stormwater runoff, particularly in urban and suburban areas (IRS Research
Company, 1972). Road salting in parts of the United States is a particu-
larly large contributor of chloride to groundwater (Hanes, et al. , 1970).
3-32
-------
Table 3-4. Examples of constituents in stormwater
runoff (Federal Water Pollution Control
Agency, 1969).
City
1. East Bay Sanitary District
Minimum
Maximum
Average
2. Cincinnati, Ohio
Maximum seasonal means
Average
3. Los Angeles County
Average 1962-63
4. Washington, D. C.
Catch-basin samples during storm
Minimum
Maximum
Average
5. Seattle, Washington
6. Oxney, England
7. Moscow, U. S. S. R.
8. Leningrad, U. S. S. R.
9. Stockholm, Sweden
iO. Pretoria, South Africa
Residential
Busines s
11. Detroit, Michigan
Criteria* for:
A. Potable water
(to be filtered)
(not to be filtered)
B. Bodv contact water
New York State
Mix.
' Mean
BOD Total Solids
mgM mg/-t
3 726
7,700
87 1,401
12 260
17
161 2,909
6
625
126
10
100** 2,045
186-285 1,000-3,500**
36 14,541
17-80 30-8,000
30
34
96-234 310-914
Suspended Solids Coliform Chlorides COD
mg/i per >* m.e!J- m°H
16 4 300
4, 400 70, 000 10, 260
613 11, 800 5, 100
1 10
227 111
!99
26 11
36,250 160
2,100 42
16, 100
40-200, 000 13-3, 100
240,000 29
230,000 28
102-213*--* 930,000--'
5,000 600--' 10
50 10
2,400 \A
-------
Water in streams consists of a base-flow fraction from seepage of
groundwater and an overland runoff fraction that is usually more min-
eralized than precipitation (Hem, 1970) but less mineralized than ground-
water. Generally, the dissolved-solids content of a stream is inversely
proportional to the discharge. Other, factor s affecting the quality of
stream waters are geochemical reactions of the water with streambed
and suspended materials, evapotranspiration, and the activity of biota
in the stream. Superimposed on all these natural processes are pollu-
tion from man's activities.
The chemical quality of streamflow ranges widely. For example, the
streamflow in many largely undeveloped drainage basins in upstate
New York and in New England is very soft and commonly has a dissolved-
solids content of less than 30 mg/-L. In contrast, the Hudson River in
southern New York and many streams in other areas of the country
receive large discharges of partly treated sewage and miscellaneous
industrial and agricultural wastes, including effluents from chemical
and paper manufacturing, fruit and vegetable processing, canneries,
and other sources. In addition, large amounts of warm water are returned
to streams after use in cooling systems by utilities and other industries.
The quality of water pumped from wells near a surface-water source
generally reflects an integration of native groundwater and the surface
water that has infiltrated during various stages and seasons.
Geraghty & Miller, Inc. (written communication, 1973) reports high iron
and manganese content in groundwater pumped from wells near several
streams in New England. They attribute this to geochemical reactions
involving the infiltrating stream waters and the streambed and aquifer
materials. Bacterial activity may also have contributed to the iron and
manganese enrichment of the groundwater. Hem (1970) notes briefly
the role of bacteria in dissolving and precipitating iron and manganese.
3-34
-------
The composition of lake water is affected by many of the same factors
influencing streams, and also by incomplete mixing of water within a
lake, thermal stratification, evaporation, and the character of the sub-
surface and surface inflows to a lake. Surface water commonly has a
much higher annual range in temperature than groundwater (Rorabaugh,
1956); consequently, induced infiltration from a surface source may
cause temperature changes of as much as 5 to 10 degrees C. or more
in nearby groundwater (Figure 3-10). There is generally a lag between
changes in temperature in a surface-water body and in the hydraulically
interconnected groundwater; above-normal groundwater temperatures
near a stream or lake reflect summer infiltration, while below-normal
temperatures reflect winter infiltration of surface water.
Pollution Movement
In places where a surface-water body is closely connected hydraulically
with an underlying aquifer, water will move in the direction of the
hydraulic gradient. In different reaches of a stream channel, the stream
may have gaining or losing characteristics (i. e. , it receives ground-
water inflow or loses water to an aquifer). In reaches where the water
level in the stream is above the adjacent land surface, as for example
during a flood or where levees line the banks, part of the seepage from
the stream may become temporary bank storage and return to the
stream.
Figure 3-11 shows a pattern of flow from groundwater to surface water
that carried hexavalent chromium (Perlmutter and Lieber, 1970).
Figure 3-12 shows the concentration of nitrate (Perlmutter and Koch,
1972) that seeped into gaining streams from an interconnected shallow
aquifer.
Flow from surface water to groundwater takes place -where wells are
installed near a stream or lake and the -water pumped from the aquifer
3-35
-------
OBSERVATION WELLS
R5 R4
OHIO RIVER
R3
R2 Rl PW
PUMPED WELL
OBSERVATION WELLS
L i
BEDROCK
TEMPERATURES ARE IN
DEtREES FAHRENHEIT
HORIZONTAL AND VERTICAL SCALES
50
. I
100
ISO FEET
Figure 3-10. Section across the Ohio River near Louisville,
Kentucky, showing the distribution of lines of
equal temperature of water during a pumping
test of a well. Note downward movement of
warm water from the river toward the pumped
well (Rorabaugh, 1956).
-------
NW SE
Zone of inflow of uncontaminated water Zone of inflow of Zone of dilution
(No plating wastes) contaminated water
c
(1
UD
0>
(B) ir
o
1
91
"o
*;
(A)
u Uj n Q.
OS £$
UJ > ** ° c
i < > o c
kl
^
*'tl'
(A)
Stream-samplinK point
Location of Section N-N1
Figure 3-11. Relation of the pattern of groundwater flow
to the occurrence and dilution of plating
wastes in Massapequa Creek, South Farm-
ingdale, Long Island, N. Y. (Perlmutter
and Lieber, 1970).
3-37
-------
OJ
oo
Figure 3-12. Average content and daily load of nitrate in water at gaging
stations on selected gaining streams in sewered and un-
sewered areas, southern Nassau County, Long Island, N. Y. ,
1966-70 (Perlmutter and Koch, 1972).
-------
is replaced in part by induced infiltration of surface water as shown in
Figure 3-9. The hydraulic relations, yields of wells, and methods for
calculating stream depletion by pumping wells have been discussed by
Jenkins (1970), by Reed and others (1966) on the basis of field tests at
Kalamazoo, Michigan, by Rorabaugh (1956) for the Louisville, Kentucky
area, and by Kazmann (1948), who investigated horizontal collector
wells near Charlestown, Indiana. Under conditions of long-term steady
flow, most of the water pumped from a well may be derived from a
nearby interconnected surface-water source. The quantity of surface
water that moves into an aquifer depends on the transmissivity of the
aquifer, the hydraulic conductivity and the area of the bottom of the
stream or pond, the pumping rate, and the amount of surface water that
is available. The appearance of coliform bacteria in water from a
municipal well, located 180 feet from the Susquehanna River in upsate
New York, is attributed partly to dredging of the river bed. This may
have increased the opportunity for induced infiltration of the polluted
river water (Randall, 1970).
Control Methods
Effective programs to improve the quality of water in streams and lakes,
through control of waste disposal and storm runoff, -will also be effective
in improving the quality of groundwater fed by these surface-water
bodies.
Control of pumping, and proper siting of wells through aquifer tests and
other hydrogeologic evaluation, will help to minimize seepage of polluted
surface water into an aquifer.
Monitoring Procedures
Monitoring of the quality of surface water bodies in all reaches where
groundwater can be affected will provide the data needed to define areas
where surface water may pollute aquifers.
3-39
-------
Periodic sampling of existing wells should be programmed where justi-
fied by the threat of contamination from nearby surface-water bodies,
with chemical analyses tailored to detect the contaminants involved.
Special observations wells may be warranted to provide advance warn-
ing of flow between the surface and subsurface bodies.
References
1. Deutsch, M. , Ground-Water Contamination and Legal Controls in
Michigan, U. S. Geol. Survey Water-Supply Paper 1691, 78 pp.
(1963).
2. Federal Water Pollution Control Admin. , Water Pollution Aspects
of Urban Runoff, Bull. WP 20-15, Federal Water Pollution Control
Admin., 272pp. (1969).
3. Fuhriman, D. K. , and Barton, J. R. , Ground-Water Pollution in
Arizona, California, Nevada, and Utah, U. S. Environmental
Protection Agency Water Pollution Control Research Series,
16060 ERU 12/71, 249 pp (1971).
4. Hanes, R. E. , Zelazny, L. W. , and Blaser, R. E. , Effects of
Deicing Salts on Water Quality and Biota, Highway Research
Board, National Cooperative Highway Research Program, Rept. 91,
70 pp. (1970).
5. Hem, J. D. , Study and Interpretation of the Chemical Character-
istics of Natural Water, U. S. Geol. Survey Water-Supply Paper
1473, 363 pp. (1970).
6. IRS Research Company, Water Pollution Aspects of Street Surface
Contaminants, San Mateo, California; Environmental Protection
Agency Office of Research and Monitoring Rept. R2-72-081,
236 pp. (1972).
7. Jenkins, C. T. , Computation of Rate and Volume of Stream
Depletion by Wells, U. S. Geol. Survey Techniques of Water
Resources Investigations, Bk. 4, Chap. D-l, Washington, D. C. ,
17 pp. (1970).
8. Kazmann, R. G. , "River Infiltration as a Source of Ground-Water
Supply," Trans. Amer. Soc. Civil Engineers, Vol. 113, pp. 404-
424 (1948).
3-40
-------
9. Perlmutter, N. M. , and Koch, E. , "Preliminary Hydrogeologic
Appraisal of Nitrate in Ground Water and Streams, Southern
Nassau County, Long Island, New York, " U. S. Geol. Survey
Prof. Paper 800-B, pp. B225-B235 (1972).
10. Perlmutter, N. M. , and Lieber, M. , Dispersal of Plating Wastes
and Sewage Contaminants in Ground Water and Surface Water,
South Farmingdale, Massapequa Area, Nassau County, New York,
U. S. Geol. Survey Water-Supply Paper 1879-G, 67 pp. (1970).
11. Randall, A. D. , "Movement of Bacteria from a River to a Municipal
Well —A Case History, " Jour. Amer. Water Works Assoc. ,
Vol. 62, No. 11 (1970).
12. Reed, J. E. , Deutsch, M. , and Wiitala, S. W. , Induced Recharge
of an Artesian Glacial Drift Aquifer at Kalamazoo, Michigan,
U. S. Geol. Survey Water-Supply Paper 1594-D, 62pp. (1966).
13. Rorabaugh, M. I. , Ground Water in Northeastern Louisville,
Kentucky, •with Reference to Induced Infiltration, U. S. Geol.
Survey Water-Supply Paper 1360-B, 168 pp. (1956).
3-41
-------
THE ATMOSPHERE
Scope of the Problem
Raindrops falling through the atmosphere pick up varying concentra-
tions of dissolved solids from particles suspended in the air. Some
of the solids originate from natural sources, such as airborne salt
particles; their concentration is small. Much higher concentrations of
suspended particles and many more constituents result from man's
air-polluting activities, including industrial, automotive, and urban
sources. Where air pollution exists, raindrops may pick up enough
solids to become a source of groundwater pollution.
Nature of the Pollutants
Precipitation, including rain, snow, and dry fallout of particulate
matter, varies in composition from place to place, from storm to storm,
and from season to season. The wide range in composition of precipita-
tion has been discussed by Carroll (196Z) and Gambell and Fisher (1966).
The dissolved and particulate matter in precipitation is of local and
transported origin and is derived from the oceans, land masses, vege-
tation, industrial processes, fertilization and cultivation of the soil in
agricultural areas, combustion of fuels, and other sources. The analy-
ses in Table 3-5 show the range in content of major cations and anions
in precipitation collected at selected localities in the United States prior
to 1962. The concentrations of all the listed constituents are well below
recommended limits in drinking water, but even at these low concentra-
tions, the annual fallout from precipitation represents several tons per
constituent per square mile. Other minor constituents in precipitation
include iodine, bromine, iron, lead, cadmiun, and traces of other heavy
metals (Biggs and others, 1972); silica; detergents; nitric and sulfuric
acids; and radioactive substances. Precipitation is generally acidic and
has a pH averaging about 5 to 6.
3-42
-------
Table 3-5. Chemical composition of rainwater at various
localities in the United States (Carroll, 1962).
Locality
Cape Hatteras, N. C.
San Diego, Calif.
Brownsville, Tex.
Akron, Ohio
Tallahassee, Fla.
Greenville, N. C.
Tacoma, Wash.
Urbana, 111.
Washington, D. C.
Fresno, Calif.
Indianapolis, Ind.
Albany, N. Y.
Roanoke, Va.
Ely, Nev.
Amarillo, Tex.
Glasgow, Mont.
Grand Junction, Colo.
Columbia, Mo.
Distance
From Sea
(miles)
0
0
1
*27
37
50
75
*85
85
112
=:=128
150
200
410
540
625
650
650
Average
Annual
Rainfall
(millimeters )
1, 370
277
635
889
1, 397
1, 194
2, 032
940
1, 052
240
995
914
1, 270
381
534
380
226
1, 016
Constituents, ppm
Sodium
(Na)
4. 49
2. 17
22. 30
10
. 53
18
14. 50
90
. 23
30
26
21
22
60
22
40
.69
. 33
Potassium
(K)
0. 24
. 21
1. 00
10
13
. 07
59
07
18
1.11
. 12
.09
. 13
. 14
. 23
.26
. 17
. 31
Calcium
(Ca)
0. 44
.67
6. 50
. 69
43
. 31
. 73
-
. 23
. 37
.69
43
. 32
3. 79
2. 17
1. 72
3. 41
2. 18
Chloride
(Cl)
'6. 50
3. 31
21.96
17
.66
13
22. 58
69
35
35
. 18
. 23
23
. 30
14
17
. 28
15
Sulfate
(S04)
0. 88
1.66
5. 34
1. 62
. 48
. 57
1.69
1. 20
1. 33
54
4. 00
10
1. 33
1. 05
03
1. 30
2. 37
1. 20
Nitrate
(N03)
1. 03
3. 13
1. 76
4. 68
72
2. 97
99
1. 27
2. 14
2. 94
2. 06
4. 05
3. 12
81
1.64
1. 82
2.63
3. 81
Ammonia
(NH4)
0. 11
1.15
.28
. 38
. 07
14
. 05
09
43
2. 21
. 27
. 21
21
. 35
28
75
33
44
*Distance from freshwater lake system.
U)
I
OJ
-------
The principal sources, categories, and amounts of certain air pollutants
produced by activities of man are given in Table 3-6. Concentrations of
selected heavy metals, organics, and radioactive substances as parti-
culate matter in the air are given in Table 3- 7. A part of these pollu-
tants is eventually dissolved and reaches streams and groundwater.
Table 3-6. Annual emissions of air pollution constituents
in the United States (Federal Water Pollution
Control Agency, 1969).
Motor Vehicles
Industry
Power Plants
Space Heating
Refuse Disposal
Carbon
Monoxide
Sulfur
Oxides
Nitrogen
Oxides
Hydro-
carbons
Particulate
Matter
(in millions of tons)
66
2
1
2
1
1
g
12
6
2
3
3 1
1
1
12
4
1
1
1
1
6
3
1
1
Pollution Movement
That portion of precipitation that infiltrates into the ground and is not
subsequently lost by evapotranspiration can be expected to percolate
downward to underlying aquifers. Minerals that are left in the soil
when rainfall evaporates normally will be carried down to the ground-
water by subsequent infiltration of rainfall.
The fraction of precipitation that actually reaches the groundwater varies
from near zero in arid regions to a major percentage in areas receiving
moderate to heavy precipitation on highly permeable soils. Pollutants
present in rainwater plus those picked up by the water passage through
the soil become groundwater pollutants when the water reaches the main
groundwater body.
Pollutants in precipitation falling on surface water bodies may later
reach the groundwater at some downstream location.
3-44
-------
Table 3-7. Concentrations of selected particulate contaminants in
the atmosphere in the United States from 1957 to 1961
(Federal Water Pollution Control Agency, 1969).
Suspended particulates
Benzene- soluble organics
Nitrates
Sulfates
Antimony
Bismuth
Cadmium
Chromium
Cobalt
Copper
Iron
Lead
Manganese
Molybdenum
Nickel
Tin
Titanium
Vanadium
Zinc
Radioactivity
(Micrograms per cubic meter)
Urban
Mean
104
7.6
1. 7
9.6
(a)
(a)
(a)
0. 020
(a)
0. 04
1. 5
0.6
0. 04
(a)
0. 028
0. 03
0. 03
(a)
0. 01
b4. 6
Maximum
1706
123. 9
24. 8
94. 0
0. 230
0. 032
0. 170
0. 998
0. 003
2. 50
45. 0
6. 3
2. 60
0. 34
0. 830
1. 00
1. 14
1. 200
8. 40
b5435. 0
Nonurban
Mean
27
1. 5
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Maximum
461
23. 55
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
a. Less than minimum detectable quantity.
b. Picocuries per cubic meter.
Control Methods
The primary control that can be exerted over pollutants in precipitation
is that of improvement of air quality, through regulations and enforcement
3-45
-------
actions that lead to a reduction in pollutants and to a conformance with
emission standards from stationary and non-stationary sources.
Monitoring Procedures
Monitoring of atmospheric and precipitation samples is required to
verify the effectiveness of control methods.
References
1. Biggs, R. B. , Miller, J. C. , and Otley, M. J. , Trace Metals in
Delaware Watersheds, Univ. of Delaware Water Resources Center,
33 pp. (1972).
2. Carroll, D. , Rainwater as a Chemical Agent of Geologic Processes —
A Review, U. S. Geol. Survey Water-Supply Paper 1535-G, 18pp.
(1962).
3. Federal Water Pollution Control Admin. , Water Pollution Aspects of
Urban Runoff, Bull. WP 20-15, Federal Water Pollution Control
Admin. , 272 pp. (1969).
4. Gambell, A. W. , and Fisher, D. W. , Chemical Composition of Rain-
fall in Eastern North Carolina and Southeastern Virginia, U. S. Geol.
Survey Water-Supply Paper 1535-K, 41 pp. (1966).
3-46
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SECTION IV
SALT WATER INTRUSION
SEA WATER IN COASTAL AQUIFERS
Scope of the Problem
Under natural conditions fresh groundwater in coastal aquifers is
discharged into the ocean at or seaward of the coastline. If, however,
demands by man for groundwater become sufficiently large, the sea-
ward flow of groundwater is decreased or even reversed. This causes
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 intrusion in the United States, environmental conse-
quences, 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.
History
Sea water intrusion developed as coastal population centers over-
developed local groundwater 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 (Louisiana
Water Resources Research Institute, 1968). 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
4-1
-------
the height of fresh water above sea level (Todd, 1959). This
distribution, known as the Ghyben-Herzberg relation after its discov-
ers, is related to the hydrostatic equilibrium existing between the two
fluids of different densities. Although coastal intrusion is a hydro-
dynamic rather than a hydrostatic situation, the relation is a good first
approximation to the sea water depth for nearly-horizontal flow condi-
tions. Where head differences in the two fluids exist, refinements in
the relation (Luscynski and Swarzenski, 1966) give improved results.
Intrusion 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 (Task Committee on
Salt Water Intrusion, 1969; Todd, 1960). 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 1924. In the Miami area intrusion
has long been a problem and was seriously augmented by interior drain-
age canals which lowered the water table and permitted sea water to
advance inland by tidal action (Parker, et al, 1955).
In California, the large urban areas concentrated in the coastal zone
have caused sea water intrusion in 12 localities; 7 others are threatened,
and 15 others are 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.
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In Texas, intrusion is occurring in the Galveston, Texas City, Houston,
and Beaumont-Port Arthur areas (Pettit and Winslow, 1957). 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
(Luscynski and Swarzenski, 1966). The Honolulu aquifers of Hawaii
have been extensively intruded by sea •water due to continued overdraft
conditions (Todd and Meyer, 1971; Visher and Mink, 1964).
Environmental Consequences
Because of its salt content, as little as 2 percent of sea water in fresh
groundwater will make the water unusable in terms of US Public Health
Service drinking -water standards. Thus, only a small amount of intru-
sion 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 groundwater precludes any rapid displacement of the sea
water by fresh water. Prolonged abandonment 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 groundwater level, either water table or
piezometric surface, thereby reducing the fresh water flow to the
ocean. Thus, even with a seaward gradient, sea water can advance
inland. If the pumping is sufficiently great to reverse the gradient,
fresh -water flow ceases and sea water moves into the entire aquifer.
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
4-3
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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.
Pollution Movement
The interface between underground fresh and saline waters has a
parabolic form (Cooper, et al, 1964). The salt water tends to under-
ride the less-dense fresh water. When an equilibrium is established,
the sea water is essentially stationary, while the fresh water flows
seaward. The length of the intruded wedge of sea water varies
inversely •with the magnitude of the fresh water flow. Thus, a reduction
of fresh water flow is sufficient to cause intrusion; flow reversed is not
required.
Because sea water intrusion represents miscible displacement of
liquids in porous media, diffusion and hydrodynamic dispersion tend to
mix the two fluids. The idealized interfacial surface becomes a transi-
tion 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 (Visher and Mink, 1964).
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 consider-
ations suggest that the salt discharge must come from the underlying
4-4
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sea water dispersing upward into the zone. It follows that there must
be a landward sea water flow as sketched in Figure 4-1. This circula-
tion has been verified by a field investigation at Miami, Florda
(Cooper, et al, 1964).
Ground Surface
Figure 4-1. 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 (California Department of Water Resources, 1958;
Todd, 1959).
• Control of Pumping Patterns. If pumping from a coastal
groundwater basin is reduced or relocated, groundwater
levels can be caused to rise. With an increased seaward
hydraulic gradient, a partial recovery from sea water
4-5
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intrusion can be expected. Figure 4-2 illustrates the effect
of moving pumping wells inland in a coastal confined aquifer,
Pumping well;
Ocean
x-Ground surface ^Pumping wells
Ocean
Figure 4-2. Control of sea water intrusion in a
confined aquifer by shifting pumping
wells from (a) near the coast to (b)
an inland location (Todd, 1959).
Artificial Recharge. Sea water intrusion can be controlled
by artificially recharging an intruded aquifer from surface
spreading areas or recharge wells. With overdraft elimi-
nated, water levels and gradients can be properly main-
tained. Spreading areas are most suitable for recharging
unconfined aquifers, and recharge wells for confined
aquifers.
Fresh Water Ridge. Maintenance of a fresh water ridge in
an aquifer paralleling the coast can create a hydraulic bar-
rier which will prevent the intrusion of sea water. A line
4-6
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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 4-3. With a. line of recharge wells par-
alleling 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 groundwater storage
capacity. The disadvantages are high cost and the need for
supplemental water.
Recharge well
Ground surface
^f^/ii>M>Mi'»^'"--
Piezometric surface
Fresh water
Figure 4-3. 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 (California
Department of Water Resources, 1958 and 1966). A new
project underway in Orange County, California, -will
inject a combination of reclaimed wastewaters and
4-7
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desalted sea water (Gofer, 1972). Details of well con-
struction are available in a report on the Los Angeles
West Coast Basin barrier (McHwain, et al, 1970).
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 groundwater
level. Gradients can be created to limit sea water intru-
sion to a stationary wedge inland of the trough, such as
illustrated in Figure 4-4 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
Ocean
*" Salt water V stable ^ Fresh water
salt-water
wedge
Figure 4-4. Control of sea water intrusion by a
line of pumping wells creating a
trough paralleling the coast (Todd,
1959).
• Combination 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 4-5 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
Figure 4-5. 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).
• Subsurface Barrier. By constructing an impermeable sub-
surface barrier through an aquifer and parallel to the coast,
sea water would be prevented from entering the groundwater
basin. Figure 4-6 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. Leak-
age due to the corrosive action of sea water or to earth-
quakes would need to be considered in a barrier design. The
method would prove most feasible in a narrow, shallow
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alluvial canyon connecting with a larger inland aquifer.
Although expensive, a barrier would permit full utiliza-
tion of an aquifer.
EXTRACTION FIELD
IN BASIN
I ,. , I
GROUND SURFACE—
SEA LEVEL
Figure 4-6. Control of sea water intrusion by
construction of an impermeable sub-
surface 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 immediately invades the
adjoining shallow aquifers. To control such intrusion,
tide gates should be installed at the outlet of each chan-
nel. 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 (Parker, et al, 1955).
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Monitoring Procedures
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 groundwater levels and chloride concentration. The
vertical structure of the transition zone should be measured 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 will be required.
Observation wells should be measured for groundwater levels and
chloride (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
communication.
4-11
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References
1. Black, A. P. , et al, Salt Water Intrusion in Florida - 1953, Water
Survey fc Research Paper No. 9, Florida State Board of Conserva-
tion, 38 pp (1953).
2. California Department of Water Resources, Sea-Water Intrusion in
California, Bulletin 63, 91 pp plus appendices and supplements
(1958).
3. California Department of Water Resources, Ground Water Basin
Protection Projects; Santa Ana Gap Salinity Barrier, Orange
County, Bulletin 147-1, 194 pp (1966).
4. California Department of Water Resources, Ground Water Basin
Protection Projects; Oxnard Basin Experimental Extraction-Type
Barrier, Bulletin 147-6, 157 pp (1970).
5. Gofer, J.R., "Orange County Water District1 s Factory 21, "
Journal Irrigation and Drainage Division, American Society of
Civil Engineers, Vol. 98, No. IR4, pp 553-467 (1972).
6. Cooper, H. H. , Jr., et al, Sea Water in Coastal Aquifers, US
Geological Survey Water-Supply Paper 1613-C, 84 pp (1964).
7. Louisiana Water Resources Research Institute, Salt-Water
Encroachment into Aquifers, Bulletin 3, Louisiana State University,
Baton Rouge, 192 pp (1968).
8. Luscynski, N. J. , and Swarzenski, W. V. , Salt-Water Encroach-
ment in Southern Nassau and Southeastern Queens Counties, Long
Island, New York, US Geological Survey Water-Supply Paper
1613-F, 76 pp (1966).
9. Mcllwain, R. R. , et al, West Coast Basin Barrier Project 1967-
1969, Los Angeles County Flood Control District, Los Angeles,
California, 30 pp plus appendices (1970).
10. Parker, G. G. , et al, Water Resources of Southeastern Florida
With Special Reference to Geology and Ground Water of the Miami
Area, US Geological Survey Water-Supply Paper 1255, 965 pp
(1955).
11. Pettit, B. M. , Jr., and Winslow, A. G. , Geology and Ground-Water
Resources of Galveston County, Texas, US Geological Survey
Water-Supply Paper 1416, 157 pp (1957).
4-12
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12. Task Committee on Salt Water Intrusion, "Saltwater Intrusion in
the United States, " Journal of Hydraulics Division, American
Society of Civil Engineers, Vol. 95, No. HY5, pp 1651-1669 (1969).
13. Todd, D.K. , Ground Water Hydrology, John Wiley & Sons, New
York, pp 277-296 (1959).
14. Todd, D.K. , "Saltwater Intrusion of Coastal Aquifers in the United
States, " International Association of Scientific Hydrology, Publica-
tion No. 52, pp 452-561 (I960).
15. Todd, D. 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).
16. Vis her, F. N. , and Mink, J. F. , Ground-Water Resources in
Southern Qahu, Hawaii, US Geological Survey Water-Supply Paper
1778, 133 pp (1964).
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SALINE WATER IN INLAND AQUIFERS
Scope of 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 groundwater are in close proximity to natural bodies
of saline groundwater.
Saline water derived from remnants of ancient sea inundations or water
contaminated by natural mineral deposits can be found at relatively
shallow depths throughout large portions of the United States. Fresh-
water recharge has tended to flush much of the saline water from aqui-
fers during recent geologic time, but saline water remains at depth or
where the movement of groundwater is restricted. Brines occur in
almost all areas at the depths explored and developed by the oil
industry.
Saline water in inland aquifers may be derived from one or more of the
following sources (Task Committee on Salt Water Intrusion, 1969):
• 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 freshwater aquifer, salt-
water intrusion results.
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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 than 1, 000 ppm
dissolved solids) (Feth, 1965; Feth, et al, 1965; Task Committee on
Salt Water Intrusion, 1969). These reports indicate that approxi-
mately two-thirds of the conterminous United States is underlain in
part by saline groundwater.
In the Atlantic and Gulf Coastal Plain and in many groundwater basins
on the Pacific Coast, saline water occurs because of sea water that
was trapped in the sediments during deposition 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 400 feet. Aquifers with saline waters of more
than 1, 000 ppm dissolved solids underlie fresh-water aquifers through-
out most of the Great Plains area from central Texas to Canada. In
the mountainous area from the Rocky Mountains to the Pacific Coast,
saline water occurs at depth in many groundwater basins.
Environmental Consequences
Intruded fresh-water aquifers typically are locally affected. Because
of the relatively slow movement of groundwater, saline water intrusion
may produce detrimental effects on groundwater quality that could per-
sist for months under the most favorable circumstances, or many
years or decades in other cases.
Causal Factors
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
4-15
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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 of natural barriers may also per-
mit 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
groundwater level to be lowered, which in turn can cause an upconing
of the saline water into the aquifer and eventually the well itself
(Winslow and Doyel, 1954). Figure 4-7 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 4-8 illustrates the zone of saline
water intrusion produced when a water table is lowered. This indi-
cates that encroachment of saline water can be a potential problem
where flood control or other projects modify stream stages.
Extensive pollution of freshwater 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 4-9.
4-16
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Ground Surface
Fresh Water
Initial Water Table
\ Water Table
Interface Reaching
the Well
Saline Water
Initial Interface
Figure 4-7. Schematic diagram of upconing of
underlying saline water to a pumping well.
4-17
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Lowered water tables
V
\
Zone of saline water intrusion
Original fresh saline water interfa.ee T
Figure 4-8. Diagram showing upward migration of saline water caused by lowering
of water levels in a gaining stream (Deutsch, 1963).
-------
Fresh water well
Corroded casing
^-—T
Abandoned open hole
Aquiclude ' '-
Figure 4-9. 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 4-10. Here a
combination of four causal factors — natural and man-made — has led
to intrusion in two distinct aquifers. Although the intruding water
shown here is sea water, the mechanisms apply equally to any saline
water source. Saline intrusion by downward seepage from surface
sources and from brine injection wells is described elsewhere.
Pollution 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 pumping
this upconing rises to successively higher levels until eventually it may
reach the well. When pumping is stopped, the denser saline water
tends to subside to its original position.
4-19
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SHALLOW GROUND WATER
DEEPER GROUND WATER <,
* « « « . o
I | Cloy
LEGEND
l.li «| Sond and Gravel
Salt Water
NOTE
I. Direct 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 surface waters or
degraded ground water through wells
Figure 4-10. Illustrative sketch showing four mechanisms
producing saline water intrusion in Southern
Alameda County, California (after California
Department of Water Resources, I960).
4-20
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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 groundwater while minimizing the under -
mixing 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 upon the direction of the head differential. Also, head dif-
ferences 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 may take the form of
actual termination of pumping, of reduction in the pumping
rate from individual wells, or of the decentralization of
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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 4-11 from the Honolulu aquifer. Here
underlying saline water (actually sea water) in a nearby
observation well moves upward and downward in accor-
dance with the pumping rate of a well.
« Increased Groundwater Levels. In situations where surface
construction or excavations have lowered groundwater
levels and caused underlying saline groundwater to rise
(see Figure 4-8), any action which raises the groundwater
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.
• 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 accom-
plished 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 under-
ground freshwater resources without increasing intrusion.
The method was successfully applied to counteract a
growing intrusion problem in Brunswick, Georgia (Gregg,
1971).
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10
440
400
O
360
J20
I9M
196:
1966
1968
1969
YEARS
Figure 4-11. Monthly variations of total draft and chloride
content in a nearby observation well, Honolulu
aquifer (after Todd and Meyer, 1971).
4-23
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• Sealing Wells. 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 pro-
vides an effective guarantee of impermeability, particu-
larly in a deep well. Preferably, a clay or cement slurry
should be pumped into the well, filling from the bottom
upward. When the material solidifies, it will 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
drilling 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
freshwater production are selected. Perforations should
be placed only opposite the fresh-water zones. Unperfo-
rated 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 zones. The
seals may be of bentonite or cement grout. Details of
well construction are available in standard references
(Campbell and Lehr, 1973; Gibson and Singer, 1971; Todd,
1959).
Monitoring Procedures
When fresh-water aquifers need to be protected against vertical
intrusion, a monitoring network to verify the effectiveness of the con-
trol method should be installed. In general, the network will consist of
observation wells perforated within the fresh-water zone and sampled
4-24
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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
abandoned wells or test holes are properly sealed.
Regular measurements of pumping rates and groundwater level
fluctuations, both natural and artifically produced, will help to recog-
nize causal factors responsible for actual or incipient intrusion
problems.
-------
References
1. California Department of Water Resources, Intrusion of Salt Water
into Ground Water Basins of Southern Alameda County, Bulletin
81, 44 pp (1960).
2. Campbell, M. D. , and Lehr, J. H. , Water Well Technology,
McGraw-Hill, New York, 681 pp (1973).
3. Deutsch, M. , Ground-Water Contamination and Legal Controls in
Michigan, US Geological Survey Water-Supply Paper 1691, 79 pp
(1963).
4. Feth, J. H. , Selected References on Saline Ground-Water
Resources of the United States, US Geological Survey Circular
499, 30 pp (1965).
5. Feth, J. H. , et al, Preliminary Map of the Conterminous United
States Showing Depth to and Quality of Shallowest Ground Water
Containing More than 1000 Parts Per Million Dissolved Solids,
US Geological Survey Hydrologic Invests. Atlas HA-199 (1965).
6. Gibson, U. P. , and Singer, R. D. , Water Well Manual, Premier
Press, Berkeley, California, 156 pp (1971).
7. Gregg, D. O. , "Protective Pumping to Reduce Aquifer Pollution,
Glynn County, Georgia, " Ground Water, Vol. 9, No. 5, pp 21-29
(1971).
8. 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).
9. Task Committee on Salt Water Intrusion, "Saltwater Intrusion in
the United States, " Journal of Hydraulics Division, American
Society of Civil Engineers, Vol. 95, No. HY5, pp 1651-1669 (1969).
10. Todd, D. K. , Ground Water Hydrology, John Wiley & Sons, New
York, pp 115-148 (1959).
11. Todd, D. 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).
12. 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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SECTION V
POLLUTION FROM DIVERSION OF FLOW
EFFECTS OF URBAN AREAS
Scope of the Problem
Urbanization is the concentration of people and of domestic, commer-
cial, and industrial structures in a given geographic area. Urban areas
commonly include both suburban and central city complexes. The rapid
trend toward urbanization is indicated by the fact that more than two-
thirds of the nation's population now reside in urban centers that occupy
about 7 percent of the land area of the United States. By the year 2000
the urban population may include as much as three-fourths of the popu-
lation (Thomas and Schneider, 1970).
This concentration of people and their activities results in a concentra-
tion both of water resources and of the wastes produced. Water may be
diverted and conveyed to an urban area from sources hundreds of miles
away. An example is the Los Angeles-San Diego metropolitan complex
which receives water from the Colorado River and from Northern Cali-
fornia. Runoff and infiltration in urban areas are markedly different
than in the original undeveloped area. Thus, urban areas produce
hydrologic and hydraulic problems connected with development of water
supplies (Schneider and Spieker, 1969); increases in peak streamflows
(Rantz, 1970); and increased mineralization of water resources due to
changes inland-use patterns (Leopold, 1968). These urban-area prob-
lems are discussed briefly in the material that follows. They are
treated in more detail elsewhere in this report.
Seawater intrusion in coastal aquifers is often associated with urban
areas due to overpumping, reduction in natural recharge, and some-
times loss of recharge from septic systems that have been replaced by
public sewers. Runoff from urban areas is heavily polluted, especially
the initial flows (IRS Research Company, 1972; Sartor and Boyd, 1972).
5-1
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Urban leachate, the source of ground-water pollution, owes its compo-
sition to dissolved organic and inorganic chemical constituents derived
from a multiplicity of sources such as dirty air and precipitation,
leaching of asphalt streets, inefficient methods of waste disposal, and
poor housekeeping techniques at innumerable domestic and industrial
locations (Hackett, 1969). Urban leachate can be a direct contributor
to stream pollution because many urban centers are located in lowlands
adjacent to large streams. In reverse, groundwater withdrawals may
permit flow of polluted water from streams to hydraulically intercon-
nected aquifers. The expansion of densely populated urban and suburban
developments into former rural or heavily fertilized agricultural areas
has compounded the problem of groundwater pollution by causing a
mingling of the effluent from cesspools and septic tanks with fertilizer-
contaminated groundwater. Moreover, in many urban and suburban
areas, wastes that are accidentally or intentionally discharged on the
land surface often reach shallow aquifers.
The pollutional effects of urbanization change as development proceeds.
Initially, large amounts of erosional debris are produced as the original
land surface is disturbed by construction. In the mature stage, domes-
tic and industrial sewage, street runoff, garbage and refuse are the
principal sources of pollution, which intensify with time.
Pollution from urban areas is not confined to the areas themselves or
to the immediately adjacent areas. The effects often extend for con-
siderable distances in groundwaters as well as in surface waters.
Environmental Consequences
Degradation of water quality may occur in both shallow and deep aqui-
fers. Increased mineralization, including increases in the content of
nitrogen, chloride, sulfate, and hardness of the water, has resulted in
limitations on pumping from some shallow aquifers in California and
Long Island.
5-2
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In scattered places illnesses have resulted from contamination of
water by sewage and industrial wastes. The occurrence of nitrate,
MBAS (detergent), and phosphate in groundwater in Nassau County,
Long Island, New York, has been investigated in detail by Perlmutter
and Koch (1971 and 1972). Figure 5-1 shows the location and subsur-
face extent of MBAS contamination in shallow groundwater beneath an
unsewered suburban residential area in southeastern Nassau County,
Long Island, New York. The Nassau-Suffolk Research Task Group
(1969) has made detailed studies of pollution near individual septic
systems in Long Island.
Gaining streams in Long Island also show significant contents of ni-
trate and MBAS from inflow of contaminated groundwater (Perlmutter
and Koch, 1971 and 1972; Cohen and others, 1971). High nitrogen con-
tent of groundwater in Kings County, Long Island, New York, is attri-
buted largely to long-term leakage of public sewers (Kimmel, 1972).
Contamination of shallow public-supply wells by detergents from cess-
poll effluent in Suffolk County, Long Island, New York, has resulted
in shutdowns of wells except during periods of peak demand (Perlmutter
and Guerrera, 1970). Similar problems occur in California; Nightingale
(1970) has analyzed contents and trends in salinity and nitrate in the
Fresno-Clovis area.
Urbanization grossly alters the hydrology of an area. In general, this
results in a decrease in the natural recharge to underlying groundwater
unless compensated by artificial recharge. This, in turn, has an ad-
verse effect on groundwater quality if the quality of the natural recharge
was high. The decrease is due to the impervious surfaces of an urban
area—houses, streets, sidewalks, and commercial, industrial, and
parking areas, which reduce direct infiltration and deep percolation of
precipitation (Seaburn, 1969). Peak storm runoff and total runoff is
increased but over shorter time periods, resulting in decreased
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EXPLANATION
100 200 300 400 500 FEET
Figure 5-1. Hydrogeochemical sections oblique to the direction of
groundwater flow, showing lines of equal concentration
of MBAS in Nassau County, Long Island, New York.
Contaminated water is shaded; lower limit shown at
about 0. 1 mg/liter (Perlmutter, et al, 1964).
5-4
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streambed percolation. Natural streambed recharge is further de-
creased by concrete storm drains and the lining of natural channels
for flood control purposes.
In the Santa Ana River Basin in Southern California, pollution of ground-
water has resulted from the importation by municipalities of Colorado
River water, which is high in salinity (750—850 mg/liter total dissolved
solids). Pollution has resulted from artificial recharge and also from
percolation of water used for irrigation of lawns and parks.
High local groundwater temperatures attributed to recharge of warm
water used for air conditioning have been investigated in Manhattan and
the Bronx, New York, by Perlmutter and Arnow (1953), and in Brook-
lyn by Brashears (1941). Pluhowski (1970) attributed a 5- to 80-degree
centigrade rise in the summer temperature of water in gaining streams
on Long Island to a variety of urban factors such as pond and lake
development, cutting of vegetation, increased stormwater runoff into
streams, and decreased groundwater inflow.
Wikre (1973) reported several pollution incidents related to urbaniza-
tion in Minnesota. These included drainage of surface water through
wells in sumps which produced discolored and turbid water as well as
positive coliform determinations, pollution from leachate in poorly
designed landfills, and pollution from solvents disposed of in pits and
basins. Poor housekeeping practices at an 80-acre industrial site re-
sulted in the saturation of the area with creosote and other petroleum
products over a long period of time. The severity of the creosote leach-
ing problem was recognized when the water from a nearby municipal
well developed an unpleasant taste.
Road Salts
A relatively recent and unique problem that has attracted considerable
attention is the pollution of groundwater resulting from application of
5-5
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deicing salts to streets and highways in winter. The region affected
is largely the Northeast and the North-Central states (Hanes and others
1970). The salt appears to reach the groundwater both from storage
stockpiles (Figure 5-2) and from solution of salt that has been spread
on roadways.
^CONFINING BFn
Figure 5-2. Flow pattern showing downward leaching of
contaminants from a salt stockpile and
movement toward a pumped well (Deutsch,
1963).
5-6
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Long-term degradation of groundwater quality has been the experience
of the New Hampshire High-way Department with high-way deicing salts
(Hanes and other, 1970). Year after year, chloride contents of water
in certain shallow wells rose, to concentrations of 3800 mg/liter.
Not only was the groundwater quality degraded, but also the casings
and screens of the wells were badly corroded, so that 37 -wells had to
be replaced. Deutsch (1963) reported a similar situation in Michigan
where water from -wells -was found to contain as much as 4400 mg/liter
of chloride due to infiltration of high-way salts.
An analysis of the steady-state concentration of road salt added to
groundwater was made for east-central Massachusetts (Huling and
Hollocher, 1972). Assuming an application rate of 20 metric tons of
salt per lane mile per year, and taking into account local rainfall and
infiltration values, a chloride concentration of 100 mg/liter was obtained
for the gross area. Local deviations from this regional average could
easily be from two to four times this figure, especially near major
high-ways. Wells in at least 15 communities in eastern Massachusetts
produce water containing more than 100 mg of chloride per liter.
The problem is widespread, litigation on the matter is not uncommon,
and research on alternative non-polluting substances is underway (Little,
1973).
Sources and Nature of Pollutants
Ground-water in an urban environmenta may contain almost every con-
ceivable inorganic and organic pollutant. A brief summary by source
of the principal potential urban pollutants is given in Table 5-1.
Pollution Movement
The principal mechanisms of ground-water pollution in urban areas are
infiltration of fluids placed at or near the land surface and leaching of
soluble materials on the surface. The sources of fluids include
5-7
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Table 5-1. Summary of urban ground-water pollutants
Source
Principal Potential Pollutants
Atmosphere
Precipitation
Seawater encroachment
Industrial lagoons
Cesspool, septic tank, and
sewage lagoon effluents
Leaky pipelines and
storage tanks
Spills of liquid chemicals
Urban runoff
Landfills
Leaky sewers
Stockpiles of solid raw
materials
Surface storage of solid
•wastes
Deicing salts for roads
Particulate matter, heavy metals,
salts
Particulate matter, salts, dissolved
gases
High dissolved solids, particularly
sodium and chloride
Heavy metals, acids, solvents, other
inorganic and organic substances
Sewage contaminants including high
dissolved solids, chloride, sulfate,
nitrogen, phosphate, detergents,
bacteria
Gasoline, fuel oil, solvents, and other
chemicals
Heavy metals, salt, other inorganic and
organic chemicals
Salt, fertilizer chemicals, nitrogen, and
petroleum products
Soluble organics, iron, manganese,
methane, caron dioxide, exotic industrial
wastes, nitrogen, other dissolved con-
stituents, bacteria
Sewage contaminants, industrial chemi-
cals, and miscellaneous highway pollutants
Heavy metals, salt, other inorganic and
organic chemicals
Heavy metals, salt, other inorganic and
organic chemicals
Salts
deliberate disposal through wells, pits, and basins, and seepage from
hundreds or thousands of miles of leaky storm water and sanitary sewers,
water mains, gas mains, steam pipes, industrial pipelines, cesspools,
5-S
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septic tanks, and other subsurface facilities. Some natural treatment
of the fluid occurs as it seeps downward through the soil zone; however,
large quantities of pollutants, particularly the mineral constituents,
may reach the water table in the uppermost aquifer. From there, the
polluted water may move laterally toward natural discharge areas or
toward pumping wells.
Control Methods
The following list suggests procedures that can prevent, reduce, or
eliminate pollution in urban and suburban areas. The applicability of
any particular method depends, of course, on local circumstances.
• Pre-treatment of industrial and sewage wastes before disposal
into lagoons and pits.
• Lining of disposal basins where the intent is to prevent leaching
into groundwater.
• Collection, by means of drains and wells, and treatment of
leachate derived from landfills, industrial basins, and sewage
lagoons.
• Proper management of groundwater pumping to prevent or retard
seawater encroachment in coastal aquifers.
• Creation, by means of wells, of injection ridges or pumping
troughs to retard seawater encroachment.
• Abandonment or prohibition of cesspool and septic tank systems in
densely populated areas and replacement by sanitary sewer systems.
• Proper construction of new wells and plugging of abandoned wells.
• Implementation of better housekeeping practices for land storage
of wastes, and monitoring of potential industrial polluters through
permits and on-site inspection.
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• Reduction in use of road deicing salts.
• Storage of stockpiles of chemicals under cover and on impermeable
platforms to prevent leaching; recovery and treatment of leachate
which has occurred.
• Publicizing procedures for optimal applications of lawn fertilizers
and garden chemicals to minimize potential leaching.
• Frequent and adequate cleaning of streets.
• Provision for artificial recharge with high quality water to com-
pensate for reduction in natural recharge.
• Use of high-quality water for municipal and industrial purposes
where return flow from those uses will contribute to groundwater;
alternatively, desalination of wastewaters before discharge.
• Provision for adequate treatment of runoff from urban areas prior
to discharge into streams which recharge groundwater.
Monitoring Procedures
Where urban areas use groundwater from local wells, the wells should
be monitored for pollutants that are associated with urban activities but
may not be included in standard water analyses; for example, heavy
metals. When specific threats to groundwater quality from past or
present practices of waste disposal (accidental or deliberate) can be
identified, special monitor wells may be warranted to provide advance
warning of pollutants approaching water-supply wells.
Even though local groundwater may not be a presently important source
of supply in many communities, monitoring of its ambient quality is
highly desirable in order to detect degradation and take action to reduce
or prevent further pollution.
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References
1. Brashears, M. C. Jr. , "Ground-Water Temperatures on Long
Island, New York as Affected by Recharge of Warm Water, "
Economic Geology, Vol. 36, pp. 811-828 (1941).
2. Cohen, P., Vaupel, D. E. , and McClymonds, N. E. , "Detergents
in the Streamflow of Suffolk County, Long Island, New York, "
U. S. Geol. Survey Prof. Paper 750-C, pp. 210-214 (1971).
3. Deutsch, M. , Ground-Water Contamination and Legal Controls in
Michigan, U. S. Geological Survey Water-Supply Paper 1691, 79 p.
(1963).
4. Hackett, J. E. , "Water Resources and the Urban Environment, "
Ground Water, Vol. 7, No. 2, pp. 11-14 (1969).
5. Hanes, R. E. , Zelazny, L. W. , and Blaser, R. E. , Effects of
Deicing Salts on Water Quality and Biota, Highway Research Board,
Report 91, 71 p. (1970).
6. Huling, E. E. , and T. C. Hollocher, "Groundwater Contamination
by Road Salt: Steady-state Concentrations in East Central Massa-
chusetts," Science^, Vol. 176, pp. 288-290, April 21 (1972).
7. IRS Research Company, Water Pollution Aspects of Street Surface
Contaminants, San Mateo, California, Environmental Protection
Agency, Office of Research and Monitoring Report R2-72-081,
236 pp. (1972).
8. Kimmel, G. E. , "Nitrogen Content of Ground Water in Kings County,
Long Island, New York, " U. S. Geol. Survey Prof. Paper 800-D,
pp. D199-D-203 (1972).
9. Leopold, L. B. , Hydrology for Urban Planning — A Guidebook on
Hydrologic Effects of Urban Land Use, U. S. Geol. Survey Cir.
554, 18 pp. (1968).
10. Little, Arthur D. Inc., "Salt, Safety, and Water Supply, " Interim
Report of the Special Commission on Salt Contamination of Water
Supplies and Related Matters, Commonwealth of Massachusetts,
Senate No. 1485, 97 pp. (1973).
11. Nassau-Suffolk Research Task Group, The Long Island Groundwater
Pollution Study, New York State Dept. of Health, 395 pp. (1969).
5-11
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12. Nightingale, H. I., "Statistical Evaluation of Salinity and Nitrate
Content and Trends Beneath Urban and Agricultural Areas — Fresno
California, " Ground Water, Vol. 3, No. 1, pp. Z2-29(1970).
13. Perlmutter, N. M. and Arnow, Ground Water in the Bronx, New
York, and Richmond Counties, with Summary Data on Kings and
Queens Counties, New York, N. Y. , New York Water Resources
Comm. Bull. 32, (1953).
14. Perlmutter, N. M. , and Guerrera, A. A. , Detergents and Asso-
ciated Containments in Ground Water at Three Public-supply Well
Fields in Southwestern Suffolk County, Long Island, New York,
U. S. Geol. Survey Water Supply Paper 2001-B, 22pp. (1970).
15. Perlmutter, N. M. and Koch, E. , "Preliminary Findings on the
Detergent and Phosphate Contents of Water of Southern Nassau
County, New York, " U. S. Geol. Survey Prof. Paper 750-D, pp.
D171-177 (1971).
16. Perlmutter, N. M. and Koch, E. , "Preliminary Hydrogeologic
Appraisal of Nitrate in Ground Water and Streams, Southern
Nassau County, Long Island, New York, " U. S. Geol. Survey Prof.
Paper 800-B, pp. B225-B235 (1972).
17. Perlmutter, N. M. , Lieber, M. and Frauenthal, H. L. , "Con-
tamination of Ground Water by Detergents in a Suburban Environ-
ment— South Farmingdale Area, Long Island, New York, " U. S.
Geol. Survey Prof. Paper 501-C, pp. 170-175 (1964).
18. Pluhowski, E. J. , Urbanization and its Effects on the Temperature
of Streams on Long Island, New York, U. S. Geol. Survey Prof.
Paper 627-D, 108pp. (1970).
19. Rantz, S. E. , Urban Sprawl and Flooding in Southern California,
U.S. Geological Survey Circular 601-B, 11 pp. (1970).
20. Schneider, W. J. and Spieker, A. M. , Water for the Cities — the
Outlook, U. S. Geol. Survey Circ. 601-A, 6 pp. (1969).
21. Seaburn, G. E. , Effects on Urban Development on Direct Runoff
to East Meadow Brook, Nassau County, Long Island, New York,
U. S. Geol. Survey Prof. Paper 627-B, 14 p. (1969).
22. Santa Ana Watershed Planning Agency, California, Final Report
to the Environmental Protection Agency (1973).
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23. Sartor, J. D. , and Boyd, G. B. , Water Pollution Aspects of
Street Surface Contaminants, EPA-R2-72-081, Office of Research
and Monitoring, EPA, 236 pp. (1972).
24. Soren, J., Ground Water and Geohydrologic Conditions in Queens
County, Long Island, New York, U. S. Geol. Survey Water-Supply
Paper 2001-A (1970).
25. Thomas, H. E. , and Schneider, W. J. , Water as an Urban Resource
and Nuisance, U.S. Geological Survey Circ. 601-D, 9pp. (1970).
26. Varrin, R. D. and Tourbier, J. J. , "Water Resources as a Basis
for Comprehensive Planning and Development in Urban Growth
Areas, " International Symposium on Water Resources Planning,
Mexico City, Vol. 2, 33 pp. (1970).
27. Wikre, D. , "Ground-Water Pollution Problems in Minnesota, "
Report on Ground Water Quality Subcommittee, Citizens Advisory
Committee, Governor's Environmental Quality Council, Water
Resources Center, Univ. of Minnesota, pp. 59-78 (1973).
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EFFECTS OF WATER CONTROL STRUCTURES
The construction and operation of structures to control surface water,
such as dams, levees, channels, floodways, causeways, and flow
diversion facilities, may in most cases have little influence on ground-
water quality. However, adverse effects are possible and an awareness
of them is important. Control measures are sometimes required. The
following subsections briefly describe some of these effects together
with suggested methods for controlling the possible resulting ground-
water pollution.
Dams
The most important effect of a dam on groundwater quality occurs
where the foundation of the structure provides a substantial or complete
cutoff of groundwater flow in an aquifer. For example, Prado Dam on
the Santa Ana River in southern California, a US Corps of Engineers
flood control structure, is located at the upper end of a narrow, V-
shaped canyon which forms the natural outlet for both surface and
groundwaters from the Upper Santa Ana Valley, an extensively
developed region. The cutoff wall extends to bedrock and blocks sub-
surface flow out of the upstream groundwater basins. Such a stoppage
reduces the hydraulic gradient of the groundwater upstream of the dam.
This causes an increased accumulation of pollutants in the groundwater,
because of slower movement or complete stoppage; the natural disposal
of salinity from the basin or aquifer is reduced or eliminated. Under
these circumstances the resulting accumulation of salts from natural or
man-made sources, such as irrigation return flows, could markedly
increase the groundwater salinity.
A second and related effect is due to the higher water table created back
of a dam. This brings the groundwater closer to the ground surface
where the opportunity for pollution from agricultural and septic system
sources, for example, may be increased. Marshy areas, swamps, and
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pools may be created; evapotranspiration losses then concentrate
salinity in the groundwater. There may also be adverse effects on
surface-water quality.
Even in situations where the dam and its foundations do not substantially
alter the total groundwater flow through the underlying aquifers, the
localized effects on groundwater levels and on the original pattern of
groundwater flow may have significant adverse impacts on groundwater
quality.
The reservoir created by the dam may have somewhat similar effects
on the groundwater of the area. If water is stored in the reservoir for
significant periods of time, the effects may be more pronounced than
those resulting from the dam itself. Seepage losses from the reservoir
also contribute to the groundwater. If the quality of the water in the
reservoir is better than that of the groundwater, improvement in
groundwater quality results. Conversely, seepage losses from a reser-
voir storing poorer quality water (eg, reclaimed water) degrade the
groundwater.
Methods to control groundwater pollution by dams could include use of
one or more of the following alternatives.
• Design the dam and its foundation so that there is a minimum
restriction to the down-valley flow of groundwater. The
feasibility of this approach will depend, of course, on the
size and type of dam as well as the geologic conditions of the
dam-site.
• Make provision for controlled releases past the dam.
* Lower the water table upstream of the dam by appropriately
placed pumping wells. This would reduce the opportunity
for pollution from ground surface sources and -would reduce
the residence time of stored groundwater. In general, water
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pumped from the wells would be of satisfactory quality for
any available local beneficial uses; if none existed, the water
could simply be released downstream of the dam. This
would increase the outflow of salts from the basin, minimizing
accumulation.
• Minimize potential sources of pollution in the area upstream
of the dam. This could involve changes in land use, reduc-
tion in application of agricultural fertilizers, or removal of
cattle from the area.
« If the reservoir is to store poor-quality water, a site should
be selected where seepage losses will be minimal. If such a
site does not exist, it may be necessary to wholly or partially
line the reservoir bottom using, for example, compacted clay.
Levees
Levees are generally low structures located along the edges of surface
water bodies such as rivers, reservoirs, lakes, and the sea to prevent
inundation of land behind the levees during periods of high water levels
resulting from floods, storms, or tides. Levees may be constructed
to form a controlled channel. Only in rare instances do levees have a
subsurface vertical extent sufficient to form a barrier to groundwater
flow.
In coastal areas levees prevent the flooding of land by seawater. As a
result, the quality of groundwater in the aquifers behind these levees is
protected. The principal harmful effect of levees on groundwater qual-
ity occurs in floodplains of rivers. The mineral quality of most flood-
waters, neglecting their suspended sediment, is higher than that of
groundwater. During periodic inundations of floodplains, some of the
water infiltrates to the groundwater and acts to improve its quality by
dilution. Where levees prevent this action and thus reduce the natural
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recharge, the mineral quality of the groundwater will tend to
deteriorate with time.
To counteract this effect which tends to degrade groundwater, two
possibilities deserve consideration. One would be to pump groundwater
from the aquifer behind the levee so as to increase the circulation of
groundwater and to remove accumulations of salinity. The other
approach would be to divert fresh water to the land behind the levee.
By overirrigation or other means of artificial recharge with water of a
quality equal to or better than that of the existing recharge, a dilution
of the groundwater similar to that produced by natural floodwaters
could be maintained.
Channels
Artificial channels are generally constructed to alter the alignment or
configuration of natural river or stream channels for some purpose
such as navigation or flood protection. In some situations, entirely new
channels are constructed. Any artificial channel •will tend to alter the
natural circulation of the groundwater. Natural recharge to the ground-
water may be increased or decreased depending upon location, depth,
and other characteristics of the new channel. Thorough investigation
of possible effects upon both quantity and quality of groundwater should
be made before undertaking a channelization project.
An important distinction in terms of their effect on groundwater quality
is whether channels are lined or unlined. A lined channel, constructed
of an impermeable material such as concrete, prevents in many reaches
the natural recharge of streamflow to groundwater. The water table
may be lowered, and groundwater circulation and dilution reduced, so
that quality is impaired.
To control this situation water needs to be artificially recharged to the
groundwater. This can be done by installation of ditches or basins for
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artificial recharge in the vicinity of the lined channel. High-quality
water diverted from the stream or derived from some other source and
released into these structures would infiltrate to the groundwater and
thus compensate for the loss of natural streambed recharge. This is
extensively practiced in California.
In unlined channels, a primary effect is that produced by changing the
water table elevation. If a channel is dredged in an area where the
water table is close to the ground surface, the new channel acts as a
drain and lowers the water table. If the groundwater body is underlain
by saline water, the reduction in freshwater head would cause the saline
•water to rise and pollute the fresh groundwater.
Methods to control this effect include:
• Install pumping wells in the underlying saline water. Removal
of a portion of the saline water by pumping will counteract its
upward movement and protect the overlying freshwater.
Means for the disposal of the saline water must be provided,
as by evaporation from lined basins, disposal to the ocean,
or desalting and use.
• Line the channel with an impermeable material. This will
prevent dewatering of the upper portion of the aquifer and
hence maintain the original natural conditions of groundwater
quality. Some drainage to prevent uplift of the channel lining
would be necessary.
There may be some loss in streambed recharge even with unlined
channels if the hydraulic characteristics are improved and the gradient
steepened, resulting in higher velocities. The effects on groundwater
quality are the same as for lined channels. Artificial recharge can be
used to compensate for the loss.
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Unlined channels may allow polluted water to enter the groundwater if
the groundwater is below the bottom of the channel and if there is no
impermeable layer above the groundwater body.
In some coastal areas (eg, Florida and California) natural channels have
been deepened or new channels excavated. These have sometimes cut
deeply into or through the underlying clay formation which originally
acted as a natural barrier and prevented the downward movement of
saline water into the underlying freshwater aquifers. Serious ground-
water pollution has resulted, as from the Los Cerritos Creek flood
channel near Seal Beach, California. Such channels should be located,
designed, and constructed with care so that the natural barriers to
saline water intrusion will not be impaired. If this is not possible, the
channels should be lined with impervious material. In some flood con-
trol channels it may be possible to install inflatable rubber dams to
prevent the movement of saline water from the sea or bay into the
channel.
Floodways or Bypass Channels
These are usually wide artificial channels constructed to carry flood-
waters that exceed the capacity of natural river channels. As such,
these are invariably unlined, and the bottom elevation is at or close to
the natural ground surface level.
The effect of most such channels on groundwater quality is minimal,
particularly as they typically carry water for only a small fraction of
each year. If anything, floodwater flowing in a bypass channel and
infiltrating into the ground would tend to improve the local groundwater
quality.
Because of the negligible effect in degrading groundwater quality, no
specific control measures are suggested.
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Causeways
A causeway is a raised highway or railway across low or wet ground,
frequently made of earthen embankments with bridged openings at inter-
vals. The principal effect on groundwater quality might be some inter-
ference with the flow of surface water which could impair groundwater
recharge, or, through ponding, increase the percolation of polluted
water. Otherwise, the effects are considered to be minimal. Proper
drainage should be provided to eliminate ponding.
Flow Diversion Facilities
Flow diversion facilities may consist of gates, locks, or weirs to
regulate the distribution and the levels of surface water. In general,
these are smaller structures than dams; consequently, the influence of
their foundations on local groundwater flows is usually minor.
Effects of the structure on groundwater quality would be analogous to
those previously described for dams. Similarly, control measures, if
required to protect groundwater quality, would be modifications of the
procedures outlined for dams.
The principal effects of operation of such structures on groundwater
quality results from the diversion of water away from its original
course for use elsewhere, thus decreasing local recharge to the
groundwater. Controlled releases past the diversion structure may be
required, sufficient in amount to provide the same volume of recharge.
or artificial recharge may be practiced to compensate for the loss.
Sewers
Sewers can pollute groundwater directly by leakage of sewage into the
ground. In addition, the reverse situation where groundwater leaks
into sewers can indirectly contribute to quality degradation. Substantial
drainage of water can occur at or just below the water table, so that
recently-infiltrated, high-quality groundwater is lost. This leaves the
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poorer-quality deeper groundwater; the average quality of the water
body is lowered. Furthermore, a lower freshwater head encourages
the upward movement of any underlying saline groundwater (see "Saline
Water in Inland Aquifers").
Because most sewers leak, especially older ones, the opportunity for
groundwater drainage into sewers exists wherever water tables are
high enough to intercept sewers. Increases in sewage flows of 20 to 25
percent after rainfalls are not uncommon. A portion of such increases
may be due to storm drains connected illegally to sanitary sewers, but
some portion is undoubtedly related to groundwater contributions.
Control methods depend upon improving the water-tightness of sewers
and are identical to those described in the section on "Sewer Leakage."
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SPILLS OF LIQUID POLLUTANTS
Scope of the Problem
Degradation of groundwater quality can result from discharge of liquid
wastes on the land surface. Some discharges are inadvertent spillages
such as motor oil dripping from automobiles and trucks, fluids released
by careless handling, and tank truck accidents. Others are deliberate
releases of waste liquids onto the ground as a disposal mechanism.
Tank trucks may habitually dump liquid wastes in open fields; this prac-
tice may be far more prevalent than is recognized. Adequate local
regulatory authority and enforcement action to halt such incidents are
often lacking.
Even in the absence of specific field evidence, general considerations
of hydrogeology and climate make it logical to assume that groundwater
quality beneath most industrial and urbanized areas is being gradually
degraded by spills of various types of liquids on the land surface. How-
ever, few investigations have been undertaken to determine the scope
of this problem so that little is known regarding the areal extent or
severity of such pollution. Chemical analyses of well -waters that
might reveal such problems are made too infrequently. Further, the
standard chemical analysis of water covers only a few of the common
troublesome constituents; other constituents that would be indicative of
particular sources of pollution, such as organics and heavy metals, are
generally not included.
Pollution stemming from liquid spills is quite variable. One example
is the degradation of groundwater quality, due to fuel spills and washing
of airplanes with various types of cleaning agents, which has been
detected at the Miami International Airport; petroleum-derived con-
taminants are floating on the water table. A second example is the
widespread contamination of groundwater resources in Maryland that
has been traced to the disposal on the land surface of crankcase oils
5-22
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drained from cars and to oil spills from trucks, railroad tank cars, and
oil drums.
The overall problem is believed to be more severe in the humid portions
of the East than in the arid regions of the country, where low precipita-
tion, low rates of groundwater recharge, and high rates of evaporation
result in less opportunity for the percolation of liquid contaminants.
Nevertheless, some notable cases of pollution of groundwaters from
surface spilling have also been reported in the West.
Environmental Consequences
Toxic chemicals spilled from trucks in road accidents or from tank rail-
road cars in detailments can enter aquifers and then begin to move
toward points of discharge such as pumping wells or nearby surface-
water bodies. A derailment of tank cars in Missouri, for example,
resulted in toxic liquids entering the ground, leading to contamination of
a spring used for public water supply and a fish kill in a nearby stream
(Missouri Mineral News, 1973).
Contaminated water or other liquids entering certain fractured rock such
as shales and granites, or rocks having large solution openings such as
limestones and dolomites, can move much more rapidly than in other
hydrogeologic environments. As a consequence, adverse effects on
water supplies some distance away from the source of the contamination
sometimes can take place before the existence of the threat is even
recognized. Municipal and private wells have been contaminated by
pickling brines and milk wastes discharged on the land surface in
Michigan (Deutsch, 1961). Sulfuric acid wastes from copper processing
plants have moved from the land surface to the water table in a large
industrial area near Baltimore, Maryland (Bennett and Meyer, 1952).
Not only was a shallow aquifer extensively contaminated, but corrosion
of the upper part of the casings in many deep •wells also allowed the acid
5-23
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to move down into deeper aquifers. A nearby municipal well showed
the effects of the pollution.
Once an aquifer has been contaminated by substances derived from spills,
the groundwater quality can remain affected for many decades even if
the source of the pollution is stopped. Thus, expensive control measures
must be implemented if the groundwater reservoir is to be purged of
the contaminant, or the use of the aquifer and perhaps of any surface
water body into which the polluted groundwater discharges must be
restricted.
Pollution Movement
In the case of a one-time spill, a large slug of liquid spread on the land
surface can seep into the ground and move as a more or less intact body
of limited size into an underlying aquifer. In the case of long-term
infiltration, on the other hand, the contaminated fluid moves continuously
downward to the water table and then may become an elongated plume
or filament stretching out from the source along the direction of the pre-
vailing groundwater gradient. This progressively degrades the subsur-
face water quality with time.
The composition, grain size, and thickness of the soil materials in the
unsaturated zone govern the movement of a contaminated fluid traveling
downward toward the water table. In many areas the materials in a
thick unsaturated zone -will filter some pollutants before they reach the
water table, and biodegradation will stabilize some organics. Where
there is an overall deficiency of moisture, the contaminated fluid may
evaporate from the soil or may adhere on rock particles as thin films
without descending to the water table. But where the unsaturated zone
is thin, there may be little retarding or adsorptive action or biodegra-
dation, so that the pollutant arrives virtually unchanged at the saturated
zone.
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Once the contaminant enters the saturated zone, its direction and rate
of travel are largely determined by the local groundwater flow pattern.
The pollutant may penetrate into the groundwater body or float on top of
the saturated zone, depending upon its density. The polluted groundwater
will move toward a natural discharge point or toward a nearby pumping
well. If the rate of movement of groundwater is slow, the pollution may
remain in the vicinity of the source of contamination for a number of
years or decades.
Control Methods
Deliberate spills of liquid pollutants can be controlled by regulation,
inspection, and enforcement action regarding the release of waste fluids
on the land surface. Such wastes can be treated by the generating organi-
zation, or they can be collected and processed by regional treatment
centers especially established for this purpose. Centers for handling
industrial wastes are increasingly available in most large urban areas.
Accidental spills cannot be wholly prevented; however, spills and their
effects on groundwater can be minimized.
• Industries handling and transporting hazardous liquids should
be required to maintain emergency facilities and trained
personnel ready to respond in case of accidents.
• Some regulatory action may be needed. In England, the
Poisonous Waste Act of 1972 requires that notice be given
to governmental agencies three days before hazardous sub-
stances are to be transported; approval is not required but
the agency may object. Both information on movements of
waste and some control over these movements result
(Todd, 1973, p. 52).
• Municipalities should inform police, firemen, and emer-
gency crews as to the dangers to groundwater inherent in
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accidental spills and should provide instruction so as to
reduce the possibility of spills and the degree of pollution
if spills do occur.
Methods for intercepting and removing oil and oil products from ground-
water are described by the American Petroleum Institute (1972) and also
under the section "Tank and Pipeline Leakage. " Methods for limiting
and eliminating pollutants dispersed within a groundwater body are
described under the section "Sea Water in Coastal Aquifers. "
Monitoring Procedures
One approach for locating potential pollution sources from liquid spills
is to investigate areas where spills of noxious liquids are known to have
taken place. As a follow-up, monitoring wells could be installed to
verify control methods and to locate the extent of any polluted ground-
water body.
Another monitoring approach is to expand the existing networks of wells
that are periodically sampled by public agencies and to substantially
improve the analytical procedures so that more determinations are made
of constituents that are indicators of contamination. Anomalous con-
centrations and long-term trends of such constituents would be noted
and investigated.
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References
1. Amer. Petroleum Institute, The Migration of Petroleum Products
in Soil and Ground Water, Amer. Petroleum Inst. Publ. No. 4149,
36 pp. (1972).
2. Bennett, R. R. , and Meyer, R. R. , Geology and Ground Water
Resources of the Baltimore Area, Maryland Dept. of Geology,
Mines, and Water Resources Bull. 4 (1952).
3. Deutsch, M. , "Hydrologic Aspects of Ground-Water Pollution, "
Water Well Journal, Vol. 15, No. 9, pp. 10-39 (1961).
4. Missouri Mineral News, Vol. 13, No. 1 (January 1973).
5. Todd, D. K. , Ground-water Pollution in Europe—A Conference
Summary, GE73TMP-1, General Electric Company, Ssnta Barbara,
Calif., 79 pp. (1973).
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LAND SURFACE CHANGES
Introduction
Changes in land surface elevation produced by overpumping of
groundwater can have unfavorable repercussions on groundwater qual-
ity. Two mechanisms can contribute to the problem. One is subsi-
dence, which is a gradual lowering of the land surface. The other is
collapse, which is the abrupt failure of the land surface due to the
movement of material into underlying cavities. The effects of these
physical changes on groundwater quality are described in the two
following subsections.
Collapse — The Sinkhole Problem
SCOPE OF THE PROBLEM. Sinkhole collapses serve as entry points
for groundwater pollution into soluble rock aquifers. Limestone ter-
ranes are most prone to sinkhole collapses, and once pollution is intro-
duced into such formations the extent of its travel can be large.
CAUSAL FACTORS. The formation of sinkholes most often results
from collapse of cavities in residual clay through solution openings in
underlaying carbonate rocks. The cavities may be caused by a lower-
ing of the water table, resulting in a loss of support to clay overlying
openings in bedrock. Other causes which are postulated include fluctu-
ation of the water table against the base of residual clay, downward
movement of surface water through openings in the clay, or an increase
in water velocity in cones of depression to points of discharge. The
geologic conditions responsible for collapses have been enumerated by
Foose (1968).
Limestone terranes are the most common locations for sinkhole
collapses. Occurrences have been reported in Alabama, Florida,
Missouri, Pennsylvania, and South Africa (Aley, et al, 1972).
Bewatering for mining has been held responsible for several collapses
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(Foose, 1967). In Missouri the construction of sewage lagoons and
small surface water reservoirs have triggered collapses, either due to
increased leakage of surface water into underground openings through
the bottom of the impoundments (Aley, et al, 1972). Some collapses
are apparently unrelated to man's activities, such as those associated
with earthquakes.
In December 1972, in Shelby County, Alabama, one of the largest
sinkholes in the United States suddenly developed (LaMoreaux and
Warren, 1973). The crater is about 140 meters long, 115 meters wide,
and 50 meters deep. The collapse may have resulted from extensive
groundwater withdrawals, but the history of water levels in the area is
unknown.
ENVIRONMENTAL CONSEQUENCES. Only recently has attention been
focused on groundwater pollution caused by collapses in limestone ter-
ranes (Aley, et al, 1972). Two aspects deserve mention. The first
concerns the increases in organic matter, bacteria, and colloidal mate-
rial in suspension released into an aquifer after the impact of a col-
lapse. The second is the artificial introduction of poor-quality water
into the underground through the depressed sinkholes. In particular,
the drainage of sewage lagoons into aquifers with numerous large solu-
tion openings can pose a serious pollutional threat. Groundwater tracer
tests using Lycopodium spores, which have a mean diameter of 33
microns, were made in limestone aquifers in Missouri (Aley, et al,
1972). Recovery of spores in springs revealed subsurface water move-
ments of as much as 40 miles in 13 days. Considering that these spores
are 10 to 15 times larger than most bacteria, the potential pollution
hazard is clear.
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CONTROL METHODS. To minimize the danger of sinkhole collapses:
• Pumping of water from limestone terranes should be
carefully regulated so as to stabilize groundwater levels
and to avoid extensive areas of dewatering
• Thorough hydrogeologic investigations should be undertaken
of any proposed sites for surface water reservoirs in lime-
stone terranes.
Subsidence — The Arsenic Problem
SCOPE OF THE PROBLEM. High arsenic concentrations found in
groundwater from deep confined aquifers in the San Joaquin Valley of
California are believed to be associated with land subsidence areas
(Fuhriman and Barton, 1971). The subsidence results from overpump-
ing of groundwater, which causes compaction of fine-grained confining
strata. At present, the phenomenon appears to be limited to one area
in California; no evidence is available of its occurrence in other land-
subsidence areas.
LOCATIONS OF LAND SUBSIDENCE. Land subsidence can occur from
a variety of causes; discussion here is limited to that produced by
excessive pumping of groundwater from deep confined aquifers.
The phenomenon of land subsidence from groundwater pumping has been
identified at several locations in the United States as well as in Japan,
Mexico, and Taiwan. Table 5-2 lists, for land subsidence locations in
the United States, the depth of compacting beds, maximum subsidence,
area of subsidence, and time of occurrence. Piezometric head
declines in the confining aquifers responsible for the subsidence range
from 30 to 150 meters.
The land-subsidence problem has been extensively studied for affected
areas in California by the US Geological Survey (Green, 1964; Lofgren
and Klausing, 1969; Poland and Green, 1962).
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Table 5-2. Description of areas of major land subsidence due to
ground-water extraction in the United States (Inter-
national Association of Scientific Hydrology, 1970).
Location
Arizona,
Central
California,
Santa Clara
Valley
California,
San Joaquin
Valley (3
areas)
L
Nevada,
Las Vegas
! Texas,
Houston-
Galveston
[ area
Louisiana,
Baton Rouge
Depth range of
compacting beds Maximum
below land subsidence,
surface, m m
100-300 2.3
50-300 4
90-900 8
60-300 1
50-600 1-2
40-900 0.3
Area of Time of
subsidence, principal
sq km occurrence
? 1952-67+
600 1920-67+
9,000 1935-66+
500 1935-63+
10,000 1943-64+
500 1934-65+
ENVIRONMENTAL CONSEQUENCES. Neglecting the serious
consequences of land subsidence on surface structures, the concern
here is the increase in arsenic content of groundwater. The US Public
Health Service drinking water standards recommend a limit of 0. 01
mg/liter for arsenic in domestic water, -while concentrations in excess
of 0.05 mg/liter are grounds for rejection of a water supply. If, as
•was found in California, a number of wells in an area show concentra-
tions of arsenic exceeding 0. 05 mg/liter, rejection of all domestic use
of groundwater in the area could follow.
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CAUSAL, FACTORS. Land subsidence results from withdrawal of
water from wells at a sufficient rate to produce a substantial decline in
the piezometric surface elevation. The decline reduces the hydrostatic
pressure within the aquifer and increases by a corresponding amount
the effective overburden pressure. This pressure creates an increased
grain-to-grain load. With time, water within a fine-grained (clayey)
confining bed adjusts to the new equilibrium conditions of the adjacent
aquifer. This produces a reduction in porosity and a migration of
water from the confining bed to the nearest aquifer. The consequent
compaction of the confining bed is evidenced by an equal decline in land
surface elevation. Figure 5-3 shows by a schematic diagram water
movement from a clayey confining layer to an aquifer and the resulting
land subsidence when the piezometric surface is lowered.
Although a causal relationship between arsenic in groundwater and land
subsidence has not yet been established, circumstantial field evidence
in California suggests that the hypothesis has validity.
The Tulare-Wasco area in the San Joaquin Valley of California is one
of the principal land subsidence regions within the State (Lofgren and
Klausing, 1969). The Allensworth-Alpaugh area, located midway
between Fresno and Bakersfield in Tulare County, lies within this large
subsidence area. Here the Corcoran Clay at a depth of about 475 feet
is one of the principal confining beds. Of 37 wells sampled in the
Allensworth-Alpaugh area, 16 were found to pump groundwater con-
taining arsenic in concentrations greater than 0. 05 mg/liter. High
arsenic values were identified as coming from wells perforated both
above and below the Corcoran Clay; however, insufficient sampling
points and well information precluded determining the exact source of
the high arsenic vertically within the groundwater basin.
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Pumping Well
Ground
Surface
Clay
Layer
Aquifer
Figure 5-3. Schematic diagram of water movement and
land subsidence •when the piezometric surface
of an aquifer confined by a clay layer is
lowered. The letter "O" refers to the origi-
nal position and "P" to the present position.
Later a test well was drilled in the same area. During drilling the
drilling mud was changed regularly and samples of the mud were ana-
lyzed for arsenic. Results indicated that high arsenic tended to occur
in clayey layers. It follows that if the clay contains arsenic and is
compacted, the arsenic will move with the displaced water into the
aquifer.
Further research on the subject is needed.
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CONTROL METHODS. As any release of arsenic into ground-water is
believed to be associated with heavily overpumped confined aquifers,
the only feasible control method is a reduction in pumping. This could
take the form of reduced pumping rates in existing wells or of reduction
in the number of wells operating in a subsiding area. Either procedure
would aid in halting the piezometric surface decline, which in turn
would terminate subsidence and the movement of arsenic into an
aquifer.
MONITORING PROCEDURES. Detection of arsenic in deep confined
aquifers would require installation and periodic sampling of observation
wells. Locations of these should be in the central portions of known or
anticipated land subsidence areas. Perforations should be placed at
aquifer depths and relatively close to thick clayey confining beds.
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References
1. Aley, T. J. , Williams, J. H. , and Mass el o, J. W. , Groundwater
Contamination and Sinkhole Collapse Induced by Leaky Impound-
ments in Soluble Rock Terrain, Engineering Geology Series No.
5, Missouri Geological Sur.vey and Water Resources, Rolla,
Missouri, 32 pp (1972).
2. Foose, R. M. , "Sinkhole Formation by Groundwater Withdrawal,
Far West Rand, South Africa, " Science, Vol. 157, No. 3792, pp
1045-1048 (1967).
3. Foose, R. M. "Surface Subsidence and Collapse by Groundwater
Withdrawal in Carbonate Rock Areas, " Proceedings 23rd Inter-
national Geological Congress, Section 12, Engineering Geology
in Country Planning, Prague, Czechoslovakia, pp 155-166 (1968).
4. Fuhriman, D. K. , and Barton, J. R. , Ground-Water Pollution in
Arizona, California, Nevada, and Utah, US Environmental Pro-
tection Agency Water Pollution Control Research Series, 16060
ERU 12/71, 249 pp (1971).
5. Green, J. H. , The Effect of Artesian-Pressure Decline on
Confined Aquifer Systems and Its Relation to Land Subsidence,
US Geological Survey Water-Supply Paper 1779-T, 11 pp (1964).
6. International Association of Scientific Hydrology, Land
Subsidence, Proceedings of the Tokyo Symposium, Publication
Nos. 88 and 89, 2 Vols, 661 pp (1970).
7. LaMoreaux, P. E. , and Warren, W. M. , "Sinkhole, " Geotimes,
p 15, March (1973).
8. Lofgren, B. E. , and Klausing, R. L. , Land Subsidence Due to
Ground-Water Withdrawal, Tulare-Wasco Area, California, US
Geological Survey Prof. Paper 437-B, 101 pp (1969).
9. Poland, J. F. , and Green, J. H. , Subsidence in the Santa Clara
Valley, California — A Progress Report, US Geological Survey
Water-Supply Paper 1619-C, 16 pp (1962).
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UPSTREAM ACTIVITIES
Scope of the Problem
The conditions governing lateral subsurface inflow, natural and artificial
outflow, recharge from the surface, and hydraulic movement of water
within a water-bearing formation will largely determine the quality of
•water that may be produced from the formation. These conditions are —
to varying degrees — amenable to controls designed to protect or improve
groundwater quality. The other principal influence on quality •within the
formation, the native mineral character of the formation itself, is not
susceptible to control; mineral constituents that enter the groundwater
through natural solution processes must be accepted as dictating the base-
line •water quality.
Man's activities in areas upstream from the recharge area of a ground-
water basin may influence the quality of the underground water. Such
influences include changing the lateral inflow, altering downward percola-
tion, introducing pollutants directly into the inflow or recharge water,
and reducing the infiltration capability of aquifer recharge areas. Some
results of upstream activities benefit the quality of a downstream aquifer;
for example, regulation by upstream reservoirs and controlled releases
downstream. However, the preponderance of effects are deleterious.
Adverse effects of upstream activities are not often identifiable in a down-
stream groundwater basin as a separable influence. Rather, a rational
program for control and abatement of the causes of deteriorating ground-
water quality must be formulated both from direct evidential data and
from an informed evaluation of indirect influences produced by an upstream
activity.
Causal Factors
The causal factors and their results are not unique to any part of the
United States. Some problems are commonly associated with mountainous
areas; others relate to humid areas, or to intensely urbanized areas.
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Control of ground-water pollution caused by upstream activities should be
formulated with an understanding of two significant geographic categories:
• Those activities occurring at the surface overlying essentially
non-water bearing formations where the effects on downstream
groundwater basins are wholly related to the surface recharge
areas of those basins. For example, in California and other
parts of the west, mountainous areas are the source for runoff
supplying the principal natural recharge to downstream ground-
water basins.
• Those activities occurring on the surface overlying an upstream
groundwater basin where hydraulic interdependencies with
downstream aquifers are related to either lateral inflow or
surface recharge. In Texas, for example, there are intimate
and immediate hydraulic relationships between the Edwards -
Trinity (Plateau) Aquifer, the Edwards (Balcones Fault Zone)
Aquifer, the Carrizo-Wilcox Aquifer, and the surface streams
rising from or cutting through these water-bearing formations.
In these two areas, California and Texas, very different conditions prevail.
Understanding the hydraulic distinction between them is essential if
measures to control activities causing adverse quality effects are to be
instituted. Some of the upstream activities with a potential for affecting
quality in downstream groundwater basins are common to both categories;
these are discussed first, followed by those activities whose effects are
unique to one category.
Environmental Consequences
Increased upstream use of surface water, with resultant evapotranspira-
tion losses from streams contributing recharge to downstream ground-
water basins, reduces the flow available for recharge and increases salt
concentrations. Generally, any sustained reduction in recharge rate will
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cause gradual deterioration of quality as a result of the relatively higher
concentration of the mineral and organic content in the remaining ground-
water. A similar adverse effect occurs -with intrusion of poor-quality
water as diminished recharge reduces the static head in the groundwater
basin.
Urbanization in upstream areas causes significant changes in the stream-
flow—both quantitatively and qualitatively. Runoff from urban areas, and
from agricultural lands under certain conditions, will carry very heavy
loadings of pollutants during small storms and in the initial phases of
large storms. While much of the urban runoff will be collected in storm
drainage systems, the effects of sheet runoff will reflect high concentra-
tions of certain types of pollutants. These pollutants may enter a down-
stream groundwater basin directly from surface recharge, or indirectly
by polluting shallow wells in stream alluvium, thence into the groundwater
by lateral flow and deep percolation.
The regimen of runoff from developed upstream areas, particularly urban,
is generally substantially different from undeveloped areas. It is char-
acterized by higher peak discharges, greater volumes, and shorter runoff
times. This tends to reduce downstream percolation and to make artificial
recharge difficult.
Diversion structures for certain types of drainage works may cause agri-
cultural runoff carrying high concentrations of agricultural pollutants to
enter streams in upstream areas, thence downstream into groundwater
basins as recharge from increased streamflow. Such levee works are
commonly constructed to reclaim marshlands for agricultural use. Thus,
the runoff from the drained lands may carry initially both heavy organic
loads and high levels of herbicide/pesticide residues.
Direct discharges of wastes upstream from the recharge area of a ground-
water basin are perhaps the most obvious sources of pollutants entering
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the basin as recharge. These discharges include the entire range of
waste-generating activities—municipal sewage, industrial wastes, saw-
mill and mining discharges, and some agricultural activities such as
feedlots.
Storm intensity and channel characteristics will have significant effects
on the recharge to downstream basins where upstream flood control is
not provided. In the Texas situation, as much as 10 cubic feet per second
of the baseflow, and ungaged but very significant percentages of the flood
flows of the Nueces River, enter the Carrizo-Wilcox Aquifer as recharge.
Generally speaking, surface floodflow (after an initial surge of flushed
pollutants picked up from land runoff) and controlled releases from
reservoirs will be of better quality than stream baseflows. Thus, flood-
control reservoirs may improve the quality of water recharging down-
stream groundwater basins by trapping sediment and providing sustained
regulated flow. In mountainous terrain, on the other hand, conservation
reservoirs impounding streamflow for the purpose of firming an out-of-
basin export may decrease available downstream recharge to a significant
extent.
Watershed management practices (Sopper, 1971) involving changes in
ground cover overlying a groundwater basin may result in significant
elevation of water tables with high concentrations of leached near-surface
pollutants—both man-made and native — entering the streams as baseflow
and causing adverse quality effects in downstream aquifers. Nitrate
pollution of shallow groundwater basins in Runnels County and other
sections of West Central Texas are believed to have resulted from extensive
changes in watershed management practices, causing rising water tables
with consequent leaching of near-surface rocks. Other types of watershed
management activities may cause a decrease in recharge by causing
higher surface losses from evapotranspiration. Farm ponds and stock-
watering ponds which have been constructed in some watersheds have
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significantly impaired downstream runoff, as in Texas. Some watershed
management practices, such as selective cutting and snowpack manage-
ment in mountainous areas, may be beneficial to downstream groundwater
basins, as in Arizona.
Fire, caused either by man or natural phenomena, often has major and
catastrophic upstream effects that impact directly and over long periods
on quality in downstream aquifers. Fire changes the regimen of the
surface runoff and increases sediment production, transportation, and
deposition. The increased silt load deposited in the recharge area of
downstream groundwater basins causes a decrease in infiltration capacity,
making subsequent efforts at artificial recharge more difficult and costly.
A marked increase in organic loadings in streams is a usual result of
fire. The gradual decomposition of these organic materials, and their
percolation in recharge to groundwater basins, results in continuing and
long-term deterioration of groundwater quality. In 1934, a major flood
followed a few months after a disastrous fire on the Arroyo Seco water-
shed in the San Gabriel Mountains near Pasadena, California. The flood
deposited large amounts of sediment and organic debris in Devil's Gate
reservoir, a flood control facility overlying the recharge area of the
Raymond groundwater basin. Subsequent decomposition of the organic
matter and movement of the decomposition products into the underlying
groundwater resulted in drastic quality deterioration and forced abandon-
ment of several wells.
The erosional debris produced in upstream areas tends to seal the beds
of downstream channels, reducing infiltration of runoff and recharge of
the groundwater. If the runoff is unpolluted, this has an adverse effect
on groundwater quality.
In the case of interdependent groundwater basins, effects of activities
overlying an upstream basin may have either beneficial or adverse effects
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upon a downstream basin. Where the quality of water in the upstream
basin is superior to that in the downstream basin, pumpage from the
tributary basin will have an adverse effect on downstream basin quality
by reducing the high-quality water entering the lower basin as subsurface
inflow. On the other hand, if quality in the upstream basin in inferior
to that of the downstream basin, the converse will be true.
Effective pollution control in upstream areas will alleviate many of the
adverse quality effects in downstream basins.
Control Methods
Specific control measures to reduce the potential for groundwater pollution
from activities in upstream areas include the folio-wing:
• Adequate fire control in tributary watersheds; prompt mitigative
measures, such as re-seeding immediately after a fire.
• Forest management practices, in tributary watersheds, that
will increase high quality runoff.
• Land resource management and land use controls in upstream
areas to minimize threats to downstream groundwater quality;
new institutional arrangements would be required.
• Management of an inter-related group of groundwater basins
or aquifers as an integrated system with quality protection and
maintenance as a principal objective.
• Artificial recharge with high-quality -water to replace reduced
natural streambed percolation due to upstream use.
• Mandatory controlled releases from upstream conservation
reservoirs to maintain downstream ground-water recharge.
• Treatment of urban runoff.
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• Weather modification to increase high quality runoff for recharge;
this is probably of limited applicability.
• Regulation of tributary runoff by storage to facilitate recharge.
• Scarification of streambeds to maintain infiltration capacity.
Reference
1. Sopper, W. E. , Watershed Management, National Water Commission,
Report NWC-EES-72-028, NTIS Accession No. PB206 370, 155pp.
(1971).
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GROUNDWATER BASIN MANAGEMENT
Concept
The concept of managing a groundwater basin is analogous to the opera-
tion 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 empty at all
time but rather on varying the water level to meet predetermined supply
and demand criteria.
Groundwater basins are increasingly being recognized as important
resources for water storage and distribution. Groundwater reservoirs
have numerous advantages over surface reservoirs (Comm. on Ground
Water, 1972):
• 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.
• Useful lives are often indefinite.
The objective of groundwater basin management is generally to provide
an optimal continuing supply of groundwater of satisfactory quality at
least cost (Mack, 1971). To reach this objective requires comprehensive
geologic and hydrologic investigations, development of a mathematical
model to simulate the aquifers, economic analyses of alternative oper-
ational schemes, and finally—based on this management study —
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regulation of the basin. In most cases conjunctive use of surface water
and groundwater systems is considered in seeking a maximum water
supply at minimum cost (Todd, 1959).
Procedure
The management study leading to a basin operation consists of the com-
ponents listed in Table 5-3. These are arranged to indicate the usual
sequential order employed.
Table 5-3. Outline of a groundwater basin
management study (Comm. on
Ground Water, 1972).
Geologic Phase
Data collection and water level maps
Storage capacity and change; transmission
characteristics
Water quality analysis
Hydro logic 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 comparison 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
groundwater levels would be defined. Water quality objectives would be
set, and sources and causes of pollution carefully controlled. The arti-
ficial recharge of storm flows, imported water, or reclaimed water
could be involved. In some instances, measures to limit seawater intru-
sion and land subsidence -would be included.
Because of the dynamic nature of groundwater resource systems, a con-
tinuing 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).
Sources of Basin Pollution
Within a groundwater basin the potential sources of pollution may include
all of the possibilities described in other sections.
A pollution source unique to basin management may be artificial recharge
of groundwater. In order to increase the available groundwater supply,
a basin may be heavily pumped so as to lower groundwater levels. There
after, water can be artificially and naturally recharged to fill the avail-
able 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 injec-
tion wells. If the quality of the recharged water is inferior to that of the
existing groundwater, pollution will result.
An excellent illustration is the situation in Orange County, California
(Moreland and Singer, 1969). To compensate for extensive overdraft of
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the groundwater 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 content of the
imported water, the salinity of a substantial portion of Orange County's
groundwater 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 groundwater basin requires an appropriate
institutional structure (Corker, 1971), embracing the basin to insure
that the water quality is not adversely affected. Control methods could
include the following:
• Maintaining groundwater levels below some shallow depth
so as to minimize the opportunity for pollution from surface
sources.
• Maintaining groundwater levels above some greater depth
in order to avoid upward movement of more saline and
warmer water into the aquifer.
• 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 groundwater, but imported and reclaimed waters
may not be.
• Preventing seawater 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
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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 groundwater pollution.
• Reducing salt loads by exporting saline groundwaters, waste-
waters, or brines from desalted water supplies.
• Monitoring the quality of groundwater throughout the basin
to identify and to locate any pollution sources and to verify
corrective measures.
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References
1. California Dept. of Water Resources, Planned Utilization of
Ground Water Basins: Coastal Plain of Los Angeles County,
Sacramento, 25pp. (1968).
2. Committee on Ground Water, Ground Water Management, Manual
No. 40, Amer. Soc. of Civil Engineers, New York, 216 pp. (1972).
3. Corker, C. E. , Ground Water Law, Management and Administra-
tion, National Water Commission, Report No. NWC-L-72-026,
NTIS Accession No. PB 205 527, 509pp. (1971).
4. Mack, L. E. , Ground Water Management, National Water Commis-
sion, Report NWC-EES-71-004, NTIS Accession No. PB 201 536,
179 pp. (1971).
5. Moreland, J. A. , and Singer, J. A. , Evaluation of Water-Quality
Monitoring in the Orange County Water District, California, USGS
Open-File Rept. , Menlo Park, Calif., 27pp. (1969).
6. Muckel, D. C. , Replenishment of Ground Water Supplies by Arti-
ficial Means, Tech. Bull. No. 1195, Agric. Research Service,
U. S. Dept. of Agriculture, 51 pp. (1959).
7. Todd, D. K. , Ground Water Hydrology, John Wiley & Sons, New
York, pp. 200-218 (1959).
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