CLASS 3

                       CLASS 3



                May 25,  1973
                  Edited by
              Charles F. Meyer

          General Electric  Company
         Center for Advanced Studies
       Santa Barbara, California   93102

        EPA Contract No.  68-01-0759
        TEMPO Project 6311-E7H-01
                Prepared for

         WASHINGTON,  B.C.  20460


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

      "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

      "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

      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;

      "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

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

"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. "


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).


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.



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


      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

SALINE WATER AQUIFERS                                       2-1

   INTRODUCTION                                               2-1

   INDUSTRIAL INJECTION WELLS                               2-1

      Current Situation                                            2-2

      Environmental Consequences                                2-7

   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
AND DESALINATION PLANT BRINES                         2-38

GAS STORAGE WELLS                                       2-40

   References                                                2-41

   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

      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


   SEWER LEAKAGE                                             3-1

      Scope of the Problem                                       3-1

      Causal Factors                                             3-1

     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

     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


   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


     Dams                                                     5-14

      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


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).

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,

 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,

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,
 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


 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
 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
 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

Table                            Title                             Page

 2-18    Change in leachate analysis with time (Meichtry,         2-110
 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).

                              SECTION I



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
      "(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:

      "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,

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.


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


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-


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-


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,


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

 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
 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


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


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
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

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:

   •  The geologic structure of the groundwater basin or aquifer

      and its boundaries

   •  The nature and hydraulic characteristics of the subsurface


   •  Groundwater levels, and directions and rates of groundwater


   •  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


   •  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

comprehensive  single reference does not yet exist.   This limitation

should be borne in mind in consulting any of the listed references.


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


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


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

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.

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

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

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.

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


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

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


    •  Areas, sources,  rate  and quality of groundwater recharge; sur-

       face and groundwater inflow-outflow  relationships;  volume of

      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

      "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

      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

      recharge quantity and quality be controlled at the local level
      within the framework of state  or federal waste discharge

   •  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.

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

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).

                          SECTION II

                   INJECTION WELLS INTO

                 SALINE WATER AQUIFERS


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.


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


   •  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
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

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


      Table 2-1.  Distribution of existing industrial
                  waste-water injection wells among the
                  22  states having such wells in  1972
                  (Warner, 1972).


New Mexico
New York
North Carolina
West Virginia

        Table 2-2.  Distribution of injection wells by
                    industry type (Warner,  1972).
Industry Type
Refineries and natural gas
Chemical, petrochemical &
pharmaceutical companies
Metal product companies
Percent of Wells
         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)

  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
Percent of Wells
   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
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

         Table 2-7.  Type of rock used for injection
                     by industrial wells (Warner, 1972).
Rock Type
Limestone and Dolomite
Percent of Wells
          Table 2-8.  Age of injection zone of industrial
                     wells  (Warner, 1972) .
Permian — Mis sis sippian 15% }
Devonian - Silurian 15% ?
Ordovician — Cambrian 27%_J


   •  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

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


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.


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


   •  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

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.


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


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

   •  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


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.

             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

   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

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

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


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

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 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

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


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.
                   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

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


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,


Common minerals that react significantly with wastes are the acid-

soluable carbonate minerals and the  clay minerals.  Acidizing of

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

 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


 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

  Table 2-11.  Summary of information desired in subsurface
               evaluation of disposal horizon and methods
               available for evaluation.
Information Desired
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
Methods Available
for Evaluation
Cores, electric logs, radio-
active logs, sonic logs
Cores, pumping or injection
tests, electric logs
Drill stem tests, water level
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

                                                      PRESSURE GAGE
                                                      WELLHEAD PRESSURE
                                                      PRESSURE GAGE Opsi
                                                \ /
                                                      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
         Figure Z-2.  Schematic diagram of an industrial waste
                       injection well  completed in competent
                       sandstone  (modified after Warner,  1965).

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.


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.

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.


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

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.

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


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.

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.

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

   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


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.


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.


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.


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

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

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


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.


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



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.


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

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.)


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).

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
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.


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
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      Geologists Memoir  18, Tulsa, Oklahoma, 412 pp (1972).

9.     de Laguna,  W. , "Importance of Deep Permeable Disposal
      Formations in Location of a Large Nuclear-Fuel Reprocessing
      Plant,  " Disposal in  Geologic Basins — A Study of Reservoir
      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).

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
      Pollution and Control, Report OSW-RDPR-72-817 (1972).

13.   Ferris, J. G.,  "Response of Hydrologic Systems to Waste
      Storage, " Underground Waste Management and Environmental
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14.   Dryberger,  J. S. , Rehabilitation of a Brine-Polluted Aquifer,
      US Environmental Protection Agency, Environmental Protection
      Technology Series EPA-R2-72-014,  Washington, D. C. , 61 pp

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
      Commission TID-7628,  Bk.  2, pp 347-355 (1962).

17.   Goolsby, D. A. , "Hydrogeochemical  Effects of Injecting Wastes
      Into a Limestone Aquifer Near Pensacola,  Florida, " Ground
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18.   Hallden,  O. S. , "Underground Natural Gas Storage (Herscher
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      Education and Welfare,  R. A. Taft Sanitary Engineering Center,
      Technical Report W61-5, Cincinnati, Ohio, 218  pp (1961).

19.   Hubbert, M.K. ,  and Willis,  D. G. ,  "Mechanics  of Hydraulic
      Fracturing, " Journal of Petroleum Technology,  American Insti-
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      Trans., T. P.  4597,  pp 153-168 (1957).

20.   Iglehart, C. F. , "North American Drilling Activity in 1971, "
      Bulletin, American Association of Petroleum Geologists, Vol. 56,
      No. 7, pp 1145-1174 (1972).

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
      Elements Inv. Report 768 (open file),  92 pp (I960).

25.   McKinney, W. A. ,  "Solution Mining, " Mining Engineering,  pp  56-
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26.   Ostroff,  A. G. , Introduction to Oilfield Water Technology,
      Prentice-Hall, Inc. ,  Englewood  Cliffs,  New Jersey,  412 pp

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 —
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30.   Roedder,  E. , Problems in the Disposal of Acid Aluminum
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      Deeplying Permeable Formations, US Geological Survey Bulletin
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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

32.   US Department of the Interior,  Geothermal Leasing Program,
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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

34.   Van  Everdingen, A. F. ,  "Fluid Mechanics of Deep-Well
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      Memoir  10, Tulsa,  Oklahoma,  pp 32-42 (1968).

35.   Warner, D. L. ,  Deep-Well Injection of Liquid Waste, US Public
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37.   Warner, D. L. ,  Deep-Wells for Industrial Waste Injection in the
      United States  — Summary of Data, Federal Water Pollution Con-
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      by Deep-Well Injection,  " Subsurface Disposal in Geologic Basins  —
      A Study of Reservoir Strata,  American Association of Petroleum
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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).

         Land Surface
Disposal  Well

                   Septic Tank
                                               ^r-Surface Casing
                                                   .  Basalt
                                                   - Roclc
                  rv    -  i




> 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

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

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.

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
Total iron
Free CO2
Ammonia nitrogen
Albuminoid nitrogen
Nitrite nitrogen
Nitrate nitrogen
Oxygen consumed
Total hardness
Total alkalinity
Total solids
Calcium hardness
Total phosphate
. 00
<. 05
. 02
3. 1
Contaminated Water Recovered from
Native Groundwater Observation Wells
Depth 560 ft.
. 01
5. 6
. 01
4. 1
. 17
Depth 480 ft. ;
Distance 20 ft.
0. 91
18. 5
Depth 460 ft. ;
Distance 100 ft.
1. 30
<. 10
<. 001
<. 05
5. 1

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

                                   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
         _— 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).

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.

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.

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.

   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

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
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.

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.

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

10.   Schiff,  Leonard,  (Editor), Ground Water Recharge and Ground
      Water Basin Management, Proc. 1963 Biennial Conference Ground
      Water Recharge Center,  Fresno, Calif.  (1963).

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).

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

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
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

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


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

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
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

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

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.

   •  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


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.

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

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).

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).


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.


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

 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


 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



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

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

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


   •  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.

   •  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).

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


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


   •  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

      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

         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-


   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.

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

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. )

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



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


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

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.

      Table 2-13.   Groundwater composition before and after
                   spray irrigation with sewage (Larson,  I960).

Total Hardness
Nitrate Nitrogen
Nitrite Nitrogen
Ammonia Nitrogen
Total Nitrogen
Total Phosphorus
Groundwater Level

*Kjeldahl Nitrogen
14 October 1955 21
Before Spraying
0. 19
2. 6
0. 6
11' 10. 5" below
top of well
(Ammonia plus organic)
November 1958
After Spraying
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.


                           Ground Water
                               S to rag
to Creeks,
and Wells
               Ground Water
Figure 2-5.  The wastewater renovation and conservation cycle
              (Parizek,  et al,  1967).

                                Mixed Hardwoods
                                                             Red Pine
                                                                            Abandoned Fields
                           Agronomic Crops     H	
             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).

   •  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.

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


   •  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

      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.


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).

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

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).


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


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,

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

          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.

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,
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
    •  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

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


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.

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.


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.


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.

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

                               Table 2-14.  Components of domestic solid waste
                                            (expressed as percentages of total).

Paper Products
Food Wastes
Garden Wastes
Cloth, Leather
Rags, Rubber
Rocks, Dirt
Glass and
, .....








Louis- Cities Purdue
villec N.J.d Univ.6
60 45 42
18 i 12
1 12
2 1

1 2

3 10 15

10 6 6












; a.
; b-
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
Incineration, with heat recovery
Incineration, without heat recovery
Open dump burning
Contracted disposal
Other, or unspecified

Total Per Year
(Thousands of



1, 627




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

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.
            Cellulose, sugar, starch
            Protein - 6. 25N
            Other organics

 20. 73
 46. 63
  4. 50
  2. 06
  1. 15
 24. 93

 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.

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


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

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


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

fill being forced outward into the surrounding soil.  When picked up by

percolating rainwater, this increases the aggressiveness of water to

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

Table 2-17.  Leachate composition.
Determination (mg/-i)

Total hardness (CaCO2)
Iron total
Alkalinity as CaCo2
Ammonia nitrogen
Organic nitrogen
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

5. 6
8, 120
1, 805
1, 860
2, 240
no result

8, 100
no result
no result
for Sources 1 •
.1, 6 is from 1
County (1968)
Landon (1969).

5. 9
3, 260
1, 220
no result

1, 710
1, 130
9, 190
-3, Source
5 -year old

3b 4c 5c 6c
8. 3
537 8,700 500
219 1,000
no result
99 940 24
300 2,000 1,000 220

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,

                 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

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

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
5. 75
45, 070
44, 900
22, 800
1, 200
15, 600
0. 0
10, 900
76, 800
1, 190
0. 24
2, 820
Canyon Landfill
13, 629
8, 930
8, 714
8, 677
3, 042
0. 65
2, 355
1, 160
3. 76
4. 75
Such experiments as the foregoing support the conclusion previously

cited that leachate from well-designed fills is not a significant

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.

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

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.

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


      —  Class III, which may accept only inert earth-type


      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.

      -  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


    •  Avoid over irrigation of surface plantings.

    •  Divert both surface and groundwater around fill site where


   •  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.

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


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.

; Groundwater
Total Dissolved
j Solids
'; PH
; Total Hardness
i Chloride
0 -_(


7. 2
/ x~\ X *i
*"> v >y


6. 7
>5 0

Monitor Well
(mg/liter) ]

7. 3
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.

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

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

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

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).

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

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

30.    US Public Health Service, Quad-City  Solid Wastes  Project - An
      Interim Report, Junel,  1966 to May  31,  1967,  USPHS,
      Cincinnati (1968).

                             SECTION III



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


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

   •  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


   •  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

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.

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


   •  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

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


   •  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


   •  Emphasis on training of sewer maintenance  personnel

   •  Exclusion from discharge to municipal sewers of any

      materials found to be irretrievably hazardous to ground-


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.


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

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.


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


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

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

           Table 3-1.  Summary of interstate liquid pipeline
                       accidents for 1971 (Office of Pipeline
                       Safety, 1972).
Crude Oil
L. P. G.
Fuel Oil
Diesel Fuel
Jet Fuel
Natural Gasoline
Anhydrous Ammonia
No. of
% of
1. 3
42, 001
6. 953
1, 585
% of
17. 1
16. 3
5. 6
1. 5
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

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

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


The leakage of water can produce  undesirable effects if the dissolved

solids in the water introduce objectionable hardness or if the water is a


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.

           Table 3-3.  Frequency of causes of pipeline leaks
                      in 1971  (Office of Pipeline Safety,
Corrosion- external
Equipment rupturing line
Defective pipe seam
Corrosion- internal
Incorrect operation by carrier personnel
Ruptured or leaking gasket
Ruptured or leaking seal
Defective repair weld
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
33. 1
10. 1
7. 1
7. 1
2. 3
2. 0
2. 0
1. 6
1. 3
1. 0
1. 0
0. 6
100. 0

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-


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.

                 LA*D    SURFACE
                               ° o • 0°. '.v^^-viviffr^r'."  «e  c : •
                               n   &°  a   a _  QQ  Q_. A a ^_ a ^  *  - ^.   t

Figure 3-1.  Generalized shapes of spreading cones
             of oil  at immobile saturation (Comm.
             on Environmental Affairs,  1972).



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).

      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


PREVENTION.  Primary control methods emphasize three types of leak


   •  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

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,

                      Oil   Saturation   in   %
                       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

         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,

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

               Figure 3-6.  Swedish two-pump method
                            for removal of oil pollution
                            from a well (Todd, 1973).


                                                 LINE OF SECTION
                                                    FIG. 2-B
                       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).

                          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).

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


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

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

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

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.


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.


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

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

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).

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.

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.

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.

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

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).


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

       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).

Table 3-4.  Examples of constituents in stormwater
            runoff (Federal Water Pollution Control
            Agency,  1969).
1. East Bay Sanitary District
2. Cincinnati, Ohio
Maximum seasonal means
3. Los Angeles County
Average 1962-63
4. Washington, D. C.
Catch-basin samples during storm
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
Busines s
11. Detroit, Michigan
Criteria* for:
A. Potable water
(to be filtered)
(not to be filtered)
B. Bodv contact water
New York State
' Mean
BOD Total Solids
mgM mg/-t

3 726
87 1,401

12 260

161 2,909

100** 2,045
186-285 1,000-3,500**
36 14,541
17-80 30-8,000

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


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.

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


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


Flow from surface water  to groundwater takes place -where wells are

installed near a stream or lake and the -water pumped from the aquifer

                 OBSERVATION WELLS
R5              R4
R2   Rl PW
                                               PUMPED WELL
                                                                      OBSERVATION  WELLS
                          L i
                                                                      HORIZONTAL AND VERTICAL  SCALES
                                          . I
                                                         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


(B) ir

u Uj n Q.
OS £$
UJ > ** ° c
i < > o c


                                                  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).

                     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


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.

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.

1.    Deutsch, M. ,  Ground-Water  Contamination and Legal Controls in
      Michigan,  U.  S.  Geol. Survey Water-Supply Paper 1691, 78 pp.

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).

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).


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.

                             Table 3-5.  Chemical  composition of  rainwater at various

                                          localities  in the United States  (Carroll,  1962).
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.
From Sea
(millimeters )
1, 370
1, 397
1, 194
2, 032
1, 052
1, 270
1, 016
Constituents, ppm
4. 49
2. 17
22. 30
. 53
14. 50
. 23
. 33
0. 24
. 21
1. 00
. 07
. 12
. 13
. 14
. 23
. 17
. 31
0. 44
6. 50
. 69
. 31
. 73
. 23
. 37
. 32
3. 79
2. 17
1. 72
3. 41
2. 18
'6. 50
3. 31
22. 58
. 18
. 23
. 30
. 28
0. 88
5. 34
1. 62
. 48
. 57
1. 20
1. 33
4. 00
1. 33
1. 05
1. 30
2. 37
1. 20
1. 03
3. 13
1. 76
4. 68
2. 97
1. 27
2. 14
2. 94
2. 06
4. 05
3. 12
1. 82
3. 81
0. 11
. 38
. 07
. 05
2. 21
. 27
. 21
. 35
           *Distance from freshwater lake system.


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
Power Plants
Space Heating
Refuse Disposal
(in millions of tons)
3 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.

 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
(Micrograms per cubic meter)
1. 7
0. 020
0. 04
1. 5
0. 04
0. 028
0. 03
0. 03
0. 01
b4. 6
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
1. 5
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

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.

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.

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).

                             SECTION IV

                      SALT WATER INTRUSION


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.


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

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.

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

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


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

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

     intrusion can be expected.  Figure 4-2 illustrates the  effect
     of moving pumping wells inland in a coastal confined aquifer,
                   Pumping well;
                             x-Ground surface      ^Pumping wells
          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

      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

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
                                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

   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
                       *" Salt water   V stable   ^ Fresh water
          Figure 4-4.  Control of sea water intrusion by a
                       line of pumping wells creating a
                       trough paralleling the coast (Todd,
•  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

     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).

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


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

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

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).

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).


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


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.

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

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


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.

                                     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.

                                                                Lowered water tables
                                                      Zone of saline water intrusion
                   Original fresh saline water    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

                                                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.

                       SHALLOW  GROUND  WATER
                            DEEPER  GROUND WATER     <,
                      *    «       «     «     . o
         I     | Cloy
       LEGEND «| Sond  and  Gravel
Salt Water
         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).

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

     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,


    Figure 4-11.  Monthly variations of total draft and chloride
                   content in a nearby observation well,  Honolulu
                   aquifer (after  Todd and Meyer,  1971).

   •  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,


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

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


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

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

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).

                             SECTION V



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).


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.


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

                              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).

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

 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,

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,
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

        Table 5-1.   Summary of urban ground-water pollutants
      Principal Potential Pollutants


  Seawater encroachment

  Industrial lagoons

  Cesspool, septic tank, and
  sewage lagoon effluents
  Leaky pipelines and
  storage tanks

  Spills of liquid chemicals
  Urban runoff
  Leaky sewers

  Stockpiles of solid raw

  Surface storage of solid
  Deicing salts for roads
Particulate matter, heavy metals,
Particulate matter, salts, dissolved
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,
Gasoline, fuel oil, solvents, and other

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
  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,

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


    •  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.

   •  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.


 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.

 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).

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).

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).


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.

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

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


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


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


   •  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

      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


   •  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 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


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

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.


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

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.

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
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
Because of the negligible effect in degrading groundwater quality,  no
specific control measures are suggested.


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 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

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."


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

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

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


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


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

       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.


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).



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

(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


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.

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).

    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).

Santa Clara
San Joaquin
Valley (3
Las Vegas
! Texas,
[ area
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+


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.

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.

                Pumping Well
      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

Further research on the subject is needed.

 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


 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.

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).


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


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.


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

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


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

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


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


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

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

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.

   •  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.

1.    Sopper,  W. E. ,  Watershed Management, National Water  Commission,
      Report NWC-EES-72-028, NTIS Accession No.  PB206 370,  155pp.



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


   •  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 —


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).

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
         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

      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

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

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


   •  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

   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.


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).