by Wayne A. Pettyjohn
NWWA/EPA Series
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INTRODUCTION
TO
ARTIFICIAL GROUND-WATER RECHARGE
6y
Wayne A. Pettyjohn
Ground Water Research Branch
Robert S. Kerr Environmental Research Laboratory
Ada, Oklahoma 74820
US EPA REGION 4 LIBRARY
AFC-TOWER 9™ FLOOR
61 FORSYTH STREET SW
ATLANTA, GA. 30303
ROBERT S. KERR ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
ADA, OKLAHOMA 74820
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Copyright ® 1981
National Waterwell Association
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ABSTRACT
Artificial ground-water recharge has been practiced for scores of years
throughout the world. The purpose of artificial recharge is to increase the
rate at which water infiltrates the land surface in order to supplement the
quantity of ground water 1n storage. A variety of recharge techniques are
feasible. Examples Include methods that increase well yields, reduce the rate
of decline of ground-water levels, reduce land subsidence, control seawater
intrusion in coastal areas, and renovate wastewaters.
Two broad types of artificial recharge are water spreading and well sys-
tems. In the former, large areas of land may be flooded, basins constructed,
ditches or furrows excavated, or existing stream channels modified. Water is
diverted to these structures where it infiltrates. Recharge wells consist of
shallow, relatively large pits or shafts or screened wells. Waters used for
recharge commonly Include stream flow, municipal wastewaters, excess
irrigation water, and cooling water.
Examples of successful recharge projects and experiments in the United
States have been reported from Illinois, Ohio, North Dakota, Michigan,
Arizona, New York, and particularly California, among several others.
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CONTENTS
Page
Abstract ii
Figures iv
1. GROUND WATER AND ARTIFICIAL RECHARGE 1
GROUND WATER 1
ARTIFICIAL RECHARGE 3
2. ARTIFICIAL RECHARGE—CONSIDERATIONS AND METHODS 7
CONSIDERATIONS 7
ARTIFICIAL RECHARGE TECHNIQUES 8
Induced Infiltration 8
Water Spreading 10
Flooding 10
Basins 10
Ditches 10
Natural Channel Modifications 12
Irrigation 12
Recharge Pits and Shafts 12
Recharge Wells 19
3. SELECTED RECHARGE FACILITIES AND EXPERIMENTAL
SITES IN THE UNITED STATES 22
References Cited 43
iii
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FIGURES
Number
Page
1. Hydrographs of two wells in Texas 2
2. An induced infiltration supply draws water from a
stream into the ground g
3. Some induced infiltration supply systems consist of
large diameter caissons from which extend horizontal
slotted pipes (laterals) 11
4. Typical plan of basin-type recharge project 13
5. Typical plan of ditch-and-flooding recharge project 13
6. Irrigation by municipal wastewater is an attractive
means of artificial recharge 14
7. Recharge pits are excavated through fine-grained material
and penetrate the upper part of an aquifer 15
8. Abandoned gravel pits are commonly used for artificial
recharge basins 16
9. Recharge shafts are designed to provide a conduit through
materials of low permeability and permit direct access
to the aquifer 17
10. Where land is not readily available for recharge
facilities, a combination of recharge shafts and pits
permits achievement of maximum rates 18
20
11. Recharge wells are commonly screened in the injection
zone, which may be separated from the land surface
by a considerable thickness of low permeability strata
12. Some recharge wells consist of several lengths of pipe of
different diameter installed one inside the other, which
permits recharging several aquifer interbedded with
confining layers 21
13. The experimental recharge pit at Peoria obtained its
water supply from the Illinois River 23
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Figures (Continued)
Number Page
14. Geologic cross section and plan view of Minot's artificial
recharge system 26
15. Hydraulic connectors at Minot are large diameter, gravel -
filled shafts that penetrate a low permeability layer
and permit direct access of the recharge water to the
aquifer 27
16. Diagrammatic sketch of the hydrogeological conditions at an
artificial recharge site in Kalamazoo, Michigan 29
17. A large diameter collector well at Canton, Ohio captures
water from a stream and shallow aquifer and directs it
through a series of laterals extending from the bottom
of the caisson in order to recharge a deeper, heavily
pumped aquifer 31
18. Diagrammatic illustration of operation of injection/extraction
doublet 33
19. Schematic of the ground-water recharge system at Camp
Pendleton, California 36
20. Plan view of the Flushing Meadows artificial recharge facility
at Phoenix, Arizona 37
21. A subsurface dam of clay impeded the flow of ground water
in a pond and gravel filled channel in the vicinity of
Glenburn, North Dakota 39
22. Proposed artificial recharge system to improve ground-water
quality at an industrial complex 40
23. Schematic of an artificial aquifer 42
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SECTION 1
GROUND WATER AND ARTIFICIAL RECHARGE
GROUND WATER
Water from wells, seeps, and springs is derived from underground sources
and is called ground water. Vast quantities of ground water are held in tran-
sient storage in the saturated part of the earth's crust. The stored ground
water slowly migrates to streams, springs, and wells, and when it reaches and
flows from these points of discharge the quantity in the ground is reduced.
On the other hand, the amount of ground water in storage fluctuates annually.
Generally, in the spring the water table is high and there is more water in
storage than there is during late summer and fall after the water table has
declined.
Ground water is derived primarily from rain and snowmelt that infil-
trates the land surface and slowly percolates to the water table. This pro-
cess of adding water to underground storage is called natural ground-water
recharge or, simply, recharge. Where the materials forming the earth's sur-
face are coarse and the slope of the land is gentle, there is generally more
ground-water recharge than there is in areas where the strata consist of fine-
grain materials, such as shale and clay, or where the slope is steep.
Ground water in storage may be depleted at an alarming rate during
droughts due to the increased pumpage of water from wells and the decrease
in natural recharge as a result of reduced precipitation. Normally, however,
the water level recovers once the drought is over. Substantial water-level
declines also occur where, over a long period of perhaps several years, pump-
ing exceeds the natural rate of recharge.
Hydrographs (graphs of water-level fluctuation versus time) illustrating
the fluctuation of the ground-water level during a period of several years in
two wells in Texas are shown in Figure 1. The hydrograph of a well in San
Antonio, which taps the Edwards and associated limestones, illustrates not
only the annual water-level fluctuation but also the effects brought about
by periods of reduced rainfall and recharge (1956, 1963-64, 1967, 1971).
Nonetheless, the long term water level has remained rather constant, indi-
cating a net balance between recharge and discharge. Conversely, the water
level in a well tapping the Lissie-Willis sand in the Houston area is charac-
terized by a continual long term decline upon which is superimposed annual
cycles. In this case the water level declined more than 43 m (140 ft) during
a 20-year period, reflecting a considerable difference between recharge and
discharge because of pumping.
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30
30
40
40
50
50
60
60
70
70
80
60
90
90
100
uj 100
i:N BEX AR COUHTY I
EDWARDS A*D ASSOCIATED LIMESTONES'
110
120
2 MO
z> 120
a
z
<
140
150
-J 140
Hi
m 150
160
uj 160
170
180
if, 180
190
190
200
t 200
210
210
220
220
230
230
240
240
AT AUEMARWS COUNTY
USSlE-WU-US SAND
250
250
260
260
270
270
280
290
260
290
1956 57 58 59
Fiqure 1 Hydrographs of two wells in Texas In the upper case,
9 the lonq-term trend is rather constant in spite of a
few short-lived declines. In the lower case, pumping
exceeds natural replenishment and there is a long-term
decline.
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Long term water-level declines, which indicate diminishing amounts of
water in storage, may lead to several vexing problems, including reduced well
yields and, perhaps, land subsidence, the intrusion of salty water in coastal
areas, or inland the leakage into the aquifer of highly mineralized water.
The most common problem is decreased well yield, which may lead to water
shortage and rationing.
Land subsidence occurs when water is squeezed out of layers of clay, per-
mitting them to be compressed. The reduction in rock volume is expressed by
sinking of the land surface. In the southern part of the Great Valley of
California and in Mexico City, for example, maximum subsidence has probably
exceeded 5 m (15 ft) and definitely exceeded 3.3 m (10 ft) over relatively
large areas. Intrusion of sea water occurs because the removal by pumping of
fresh water allows salty ground water to migrate inland, perhaps to contami-
nate water supplies. Sea water intrusion is not uncommon along parts of the
Atlantic, Gulf, and Pacific Coastal regions of the United States.
ARTIFICIAL RECHARGE
Artificial recharge is a means of augmenting the natural infiltration of
surface water into a ground-water reservoir at a rate that vastly exceeds that
which would occur naturally. It includes a variety of methods, such as wells
or other specialized construction, water spreading, or changing natural condi-
tions. Other than induced infiltration, the two major techniques of artificial
recharge are surface spreading and injection wells. In surface spreading
methods, large areas of land may be flooded, basins constructed, ditches or
furrows excavated, or existing stream channels might be modified. Water is
diverted into these catchment structures and allowed to infiltrate. Recharge
or injection wells might consist of shallow, relatively large pits or shafts,
or screened wells. Recharge wells and shafts permit direct access from the
surface water source to the ground-water reservoir.
Artificial ground-water recharge techniques have been used throughout the
world for more than 200 years for a variety of purposes. These include but
are not limited to the following:
1. Ground-water (well field) management
2. Reduction of land subsidence
3. Renovation of wastewater
4. Improvement of ground-water quality
5. Storage of stream waters during periods of high or excessive flow
6. Reduction of flood flows
7. Increase well yield
8. Decrease the size of areas needed for water-supply systems
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9. Reduction of salt-water intrusion or leakage of mineralized water
10. Increase stream flow
11. Store fresh water, derived from rain and snowneIt. If ^ existing
ground water is saline, the less dense lens will float on tne saline
water.
12. Secondary recovery of oil
In addition to designs and structures contrived solely for
recharge, a large quantity of water and wastewater recharge
unmonitored and nondeliberate recharge. J disDosal treat-
includes, among others, the fluids that ^Jf^tratetlu^.Hlizina excavations
ment or storage facilities, particularly those methods utilizing ^avations,
mines, and ponds. It also includes the waters applied for 9 rations of
of which infiltrates to the water table carrying
a variety of dissolved salts and agricultural . t recharae
underground facilities can also lead to inadvertant ground water rectory.
Examples include leakage from pipelines and sewers. Along the sameline are
included accidental spills, which might occur by the wrecks of trains or
transport trucks, as well as leakage of fluids from storagetanks. Other
sources of nondeliberate recharge include dry w11s» JSIipJ as
Canals, w611 disposal of wastes, septic tanks, cesspools, and privies, as
well as mines.
Induced infiltration is an indirect method of ^o"^-w^er recharge.
When a well that lies close to a lake or stream ^ the water level
in the vicinity of the well declines to form a cone of depression. If the
ground-water level declines to such an extent that It J*
surface of the lake or stream, water will begin to flow Into the ground and
then toward the well. The well induces recharge I^changingw2iicHl!«»C*h!!
tions. In many cases, laffltration galleries and jojlector welJs are the
major means of extraction rather than typical vertical wells. Induced infil-
tration supplies commonly produce large amounts o
and may provide a more reliable source than wells that depend solely on
natural recharge. On the other hand, induced water supplies closely reflect
the chemical quality of surface water and if the latter becomes polluted,
the induced water may degrade the aquifer.
The water commonly used for artificial recharge includes natural stream
flow, high flows diverted from a nearby water course, or cooling waters. In
some places, storm drainage water has been collected and then allowed to in-
filtrate through basins or'wells. In many parts of the world, sewage effluent,
either treated or untreated, has served as a major source of recharge water.
This source is becoming more attractive, both technically and economically,
because water that would normally flow to waste can be effectively treated by
means of land disposal systems from whence it infiltrates, eventually to
become ground water.
Land application of wastes and wastewaters was practiced in Athens prior
to the Christian Era and effluent irrigation was reportedly used in Germany
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in the 16th century. The practice spread throughout Europe and continued in
South Africa, Australia, and Mexico as those areas were colonized. Many of
the successful farms employed underdrains to carry off the excess artificially
recharged ground water to nearby streams.
The Department of Economic and Social Affairs of the United Nations (1975)
described 31 sites, exclusive of the United States, where artificial recharge
is either practiced or has been investigated. The examples reported are not
comprehensive but rather point out the extensive use of artificial recharge
throughout the world. By far, the widest use of artificial recharge in
countries outside of the United States is to supplement dwindling municipal
and industrial ground-water supplies or to improve their quality. Advanced
techniques are utilized in Spain, Switzerland, Germany, France, Sweden, Israel,
Egypt, Algeria, Iran, and the Latvian, Lithuanian, Turkmen, Uzbek, and
Ukrainian Soviet Socialist Republics.
Artificial recharge is also extensively used to control salt-water intru-
sion in coastal areas of Australia, the Netherlands, Israel, Morrocco, Senegal,
Togo, Japan, and the United States. In Japan, artificial recharge is also
being practiced to reduce land subsidence in areas of excessive pumping and
in Romania, Bulgaria, and France it 1s used to supplement irrigation water
obtained from ground-water sources.
Artificial recharge has been practiced in the United States for nearly
a century and probably at least one system is presently being operated In
every State. The purposes of recharge vary widely, ranging from well-field
management to waste disposal. The greatest number of systems are relatively
small and are used to reduce the rate of water-level decline in order to
avoid water rationing or to supplement the yield from existing well fields.
Nearly all of the larger projects or systems are designed to either limit
salt-water Intrusion in coastal areas or to renovate sewage, or both.
Land treatment of sewage began in the United States In the late 19th
century; these systems were developed exclusively for irrigation purposes.
Seepage of water from Irrigation canals (a type of artificial recharge) in
Fresno County, California, was described as early as 1898. Even earlier
(1890) recharge ponds were constructed along the South Platte River near
Denver to Increase the yield of Infiltration galleries.
Induced Infiltration supplies for both municipal and Industrial needs are
common along most of the major waterways and particularly adjacent to the
Ohio and Mississippi Rivers and many of their major tributaries.
The largest regional effort of artificial recharge is being carried out
1n California where as early as 1895 flood waters were spread over the allu-
vial fan at the mouth of the San Antonio Canyon to sustain the flow of wells
in southern California's Upper Santa Ana Valley (Thomas and Phoenix, 1976).
By the late 1950's, more than 50 different agencies were Involved, 1n one way
or another, with artificial recharge. Most of the projects were in the San
Francisco Bay, Tulare, and southern coastal regions. About 65% of all the
projects utilized recharge basins or pits and these accounted for about 60%
of the water recharged. Natural channels, ditches, and furrows accounted for
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almost 40% of the water artificially recharged, while wells provided only
about 1%. Water used for these systems was obtained locally, from the Central
Valley, or from the Colorado River.
Nearly 40% of the water used in Los Angeles each year is derived from
aquifers that have been artificially recharged with storm runoff and other
surplus water. The value of the water approaches $50 million a year (Saines,
1974). The water is recharged through 36 spreading basins that total a
combined area of 13 square kilometers (five square miles).
The arid to semiarid climate of much of California, coupled with large
urban population centers, industry, and an enormous agricultural output based
on irrigation, has had a significant impact on the region. The extensive use
of ground water and the diversion of stream flow to reservoirs and irrigation
tracts caused significant water-level declines and reduction of stream flow.
This, in turn, led to land subsidence, largely in the Central Valley, seawater
intrusion into fresh water coastal aquifers, and induced salt water recharge
from tidal rivers, particularly in the San Francisco Bay, Central and South
Coastal Regions, and depletion of water in storage in many other places.
These adverse effects of surface and ground-water use necessitated much of
the research, experimentation and utilization of artificial recharge
techniques in tbe United States.
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SECTION 2
ARTIFICIAL RECHARGE—CONSIDERATIONS AND METHODS
CONSIDERATIONS
The type of artificial recharge system that can be developed at any speci-
fic site is controlled, to a large degree, by the geologic and hydrologic con-
ditions that exist at that site. Site selection criteria, in addition to
economic considerations, should include at least the following:
1. Source of recharge water
2. Chemical and physical characteristics of the recharge water
3. Availability of an aquifer suitable for artificial recharge
4. Thickness and permeability of the material overlying the aquifer,
if any
5. Thickness and permeability of the aquifer
6. Chemical characteristics of water in the aquifer
7. Proximity of the potential recharge site to an appropriate well
field cone of depression
8. Water-level differences between the aquifer and the recharge site
9. Topography
10. Availability of property
Availability of water, either on a perennial or intermittent basis, 1s of
prime concern in any recharge operation. In some cases, impoundment structures
may be necessary for temporary surface storage and to increase natural recharge.
The chemical and physical characteristics of the recharge water are impor-
tant for several reasons. First, the chemical quality of the surface water
must be compatible with that in the aquifer in order to avoid chemical reac-
tions that might reduce the permeability of the aquifer. Secondly, it is
essential that the recharge water does not contain toxic chemicals, such as
those derived from some industrial wastes or pesticides, since this could con-
taminate the ground-water supply. Finally, it Is advantageous to use water
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that is low in sediment (turbidity) because fine-grained materials may rapidly
plug a recharge system and perhaps reduce the permeability of the aquifer as
well.
The aquifer to be recharged must underlie the potential recharge site. In
areas of complex subsurface conditions, particularly where there is interfinger-
ing of coarse and fine-grained rock units, it is not always a simple task to
determine aquifer interconnections. Furthermore, the aquifer must have suffi-
cient permeability and thickness to rapidly carry away the recharged water.
An aquifer that is tapped by high yield wells should be suitable for artificial
recharge. Additionally, the recharge site must lie within the influence of a
well field cone of depression so that the recharged water has an opportunity of
flow down gradient in the direction of pumping rather than elsewhere.
The ttvickness and permeability of the earth materials overlying the de-
watered aquifer exert a strong Influence on the type of recharge system that
can be constructed. When these materials are thick and of low permeability,
recharge wells are in order, but where thin or more permeable, spreading
basins, large shafts, or irrigation may be satisfactory.
The water level in the aquifer must be lower than the operational water
level in the recharge system so that the water will infiltrate. The differ-
ence in water level, or the depth of water in a basin, is the driving force
that allows the water to infiltrate.
Topographic relief of a potential artificial recharge facility may limit
design capability. Water spreading, irrigation, and land treatment systems
require land that is relatively flat, while the topography may have little or
no influence on an injection well system.
In urban areas land acquisition for recharge facilities may provide a sig-
nificant hurdle, since the most favorable locations may be preempted. Industrial
areas should be avoided, if possible, because of the possibility of contamination.
ARTIFICIAL RECHARGE TECHNIQUES
Induced Infiltration
Induced infiltration supplies depend, to a large extent, on the quantity of
water that can be diverted from a stream or lake. Pumping a streamside well
establishes, a hydraulic gradient from the surface source to the well (fig. 2).
Both vertical arid horizontal wells are used for this purpose. The controlling
factor, Qthef than a -dependable source of surface water of acceptable quality,
is the permeability of the streamside deposits and the sediment on the bottom
of the stream. In areas where the stream is separated from the aquifer by
materials of low permeability, leakage from the stream may be so small that
the system mt feasible.
The permeability of a stream bottom fluctuates throughout the year. During
periods of low flow, mud and organic matter accumulate In the channel forming a
bed of low permeability that reduces infiltration. The channel 1s scoured
during high flows. The rate of infiltration can vary by 50% or more between
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periods of high and low flows. In many places, and particularly during droughts
or extended dry periods, stream discharge is not sufficient to erode the fine
materials from the channel bottom. This situation may be rectified by dredging.
Where saturated streamside deposits are thin, horizontal wells may be more
feasible and appropriate than vertical wells. Laterals which radiate from a
central collector well can be injected so that they lie close to the bottom of
the aquifer and allow the maximum amount of drawdown (fig. 3).
An important consideration in induced infiltration is the chemical quality
of the surface water source. Since a considerable percentage of the water dis-
charged from the well may be derived directly from a stream, its chemical qual-
ity will reflect that in the stream. Induced infiltration from a contaminated
stream may seriously degrade a ground-water supply. Disposal of brine into the
Tuscarawas River in eastern Ohio increased the chloride content of the river to
more than 6,000 mg/1 (milligrams per liter). Induced infiltration of the brine-
enriched river water eventually forced the abandonment of municipal wells at
Barberton and Coshocton. Even at Marietta, more than 200 river miles below the
waste source, municipal wells showed a marked increase in chloride.
Water Spreading
As the term implies, water spreading consists of allowing water to mantle a
large area at a relatively shallow depth in order to provide a substantial sur-
face area through which the water can infiltrate. Controlling factors on the
amount of artificial recharge are (1) water contact time, (2) soil permeability,
and (3) area of inundation. Todd (1959) described five different approaches to
water spreading. These include flooding, basins, ditches, natural channel
method, and irrigation.
Flooding—
Nearly level or only gently sloping land is required for flooding methods
of artificial recharge. Water is diverted by canals or other structures from
the water source to the recharge site. Surface velocities are kept to a mini-
mum in order to reduce erosion as the water flows across the recharge site to a
point of collection. Excess water that runs off the plot may be collected in a
down-gradient ditch or canal and either returned to the source stream or used
for some other purpose.
Basins-
Artificial recharge basins commonly are formed by either excavation or by
building low head dams across natural waterways (fig. 4). They commonly lie in
ephemeral or intermittent stream channels or parallel to them.
An advantage of the basin method is that whatever space is available can
be used. Furthermore, they are easy to construct and maintain. The rate of
recharge from individual basins is directly related to the permeability of the
materials between the bottom of the basin and the water table.
Ditches—
In sane areas it is feasible to excavate a series of ditches, trending
slightly down the topographic slope, that originate at a major feeder canal
10
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Stream
Figure 3. Some induced infiltration supply systems consist of
large diameter caissons from which extend horizontal
slotted pipes (laterals). These systems commonly
provide yields of several thousands of gallons per
minute.
11
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(fig. 5). This type of system may resemble a herringbone pattern. The ditches
should terminate in a collection canal designed to carry away the water that
does not infiltrate in order to avoid ponding and reduce the accumulation of
fine material. A ditch system can be designed to best suit the topographic
and geologic conditions that exist at a potential artificial recharge site.
Natural Channel Modifications—
In order to increase both the time and area of water coverage in a channel,
a number of structures can be built. Other than channel dredging, straightening
and widening, low head check dams are the most popular method for increasing
recharge from existing streams or ephemeral channels.
Irrigation-
Irrigation, particularly during the nongrowing season, may add a signifi-
cant amount of water to underground storage (fig. 6). An especially attractive
prospect is irrigation with sewage or partly reclaimed sewage. Here the advan-
tages are twofold: (1) after recharge the water is again available for reuse
and (2) the water receives a substantial amount of treatment and renovation as
it percolates through the unsaturated zone. These systems must be monitored
and managed, however, in such a way that water logging does not occur.
Recharge Pits and Shafts
From a regional point of view, conditions that permit surface spreading
methods for artificial recharge are relatively rare. In the more general case,
lenses and layers of earth materials that are only slightly permeable He
between land surface and the water table. In situations such as these, artifi-
cial recharge systems must penetrate the less permeable strata 1n order to pro-
vide direct access to the dewatered aquifer. This may be accomplished with pits,
shafts, or wells. These structures also permit construction of artificial
recharge facilities 1n relatively small areas.
Recharge pits are simply excavations, of variable dimensions, that are
sufficiently deep to penetrate less permeable strata (fig. 7). Construction
and maintenance are relatively simple and commonly inexpensive. In many places
abandoned gravel pits have served as recharge pits (fig. 8).
Unfortunately, pits used for storage or treatment of liquid wastes provide
a significant source of inadvertant recharge, which leads to complex and wide-
spread problems of ground-water pollution. Examples Include sewage treatment
lagoons, industrial waste holding or disposal ponds and oil-field brine evapora-
tion pits, to mention only a few of an exceedingly large number.
Recharge shafts are generally deeper and of smaller diameter than pits
(fig. 9). Their purpose is also to penetrate low permeability layers. Shafts
may be lined or unlined, open or filled with coarse material, and large or small.
They are constructed by hand, with draglines and backhoes or are drilled or
bored. Where the recharge water contains sediment, shafts may become plugged
fairly rapidly.
Commonly, recharge shafts are used in conjunction with pits (fig. 10).
Both suffer from decreasing recharge rates with time due to the accumulation
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Diversion structure
Main gate
measuring device
Outfall
Measuring device
Ditch
Bypass, as required y
Fence, as required
*—-—x x
r__V. Baffle, as required
Recharge
Interbasm
control
-*¦ c
Recharge
basin
*.
^ •
Recharge and
settling basin
2
Recharge and
settling basin
i"
r
/
-x-
Figure 4. Typical plan of basin-type recharge project
(Bianchi and Muckel, 1970, p. 46).
Gate and measuring device
•Diversion structure
Supply ditch
Alternate
diversion, as
required
Measuring
devi ce
—Collecting ditch
Prevailing ground slope generally
outlets
requi red
Supply ditch
Wire-bound check dams,
as requi red
Figure 5. Typical plan of ditch-and-flooding recharge
project (Bianchi and Muckel, 1970, p. 48).
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EVAPORATION
ROOT ZONE
SUBSOIL
SPRAY OR
SURFACE
APPLICATION
SLOPE
variaile
'^-OEIP
PERCOLATION
(a) IRRIGATION
EVAPORATION
SPRAY APPLICATION
ORASS AND VEOETATIVE LITTER
SHEET FLOI
SLOPE 2-8*
/-RUNOFF
/ COLLECTION
100-300 FT
(b) OVERLAND FLOW
Figure 6. Irrigation by municipal wastewater is an
attractive means of artificial recharge.
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Figure 7. Recharge pits are excavated through fine-grained
material and penetrate the upper part of an aquifer.
They are effective and easy to construct and main-
tain.
15
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O0Q
p O'O VK.Q.„» oO yi?r?oO •n- O.oO Or
.Up-rYo ^o9^o°.\
0 O°o.9rs°o ^?rv-
Jr° Pi^ (So o Vi O ^ rx"5 0 AD
-Ao *5« 'or? h o °w&p ¦*&
/£<5> » e?c> o 0 Permeable}, r
|#M: material v>:<>:
O-dlJV
oO°00Ap/
ynv»«„A"r\ Si ^ „ 2
y^-yo<£WvfrW>;D:^
Figure 8. Abandoned gravel pits are commonly used for
artificial recharge basins.
16
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Canal or pond
Low permeability
HHBmaterial"-^"-
m° ?§$$$ S-« %#&'' |ftfe^.^P«rmiab1« materia^
m mmii Pps&sspps
jgiapipi
Figure 9. Recharge shafts are designed to provide a conduit
through materials of low permeabi1ity and permit
direct access to the aquifer.
17
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Recharge shafts
Recharge pit
Low permeability
material^"—
oro' -o rv' O oO"Qv
;>« :»• • •. .O • R, o\v- .-o- :o-
^Water tablrtfTO*
Figure 10. Where land is not readily available for recharge
facilities, a combination of recharge shafts and
pits permits achievement of maximum rates.
18
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of fine-grained materials and to the plugging effect brought about by microbial
activity. Rates through recharge pits may be maintained by periodically allow-
ing the facility to become dry or by scraping and removing the accumulated
material from the sides and bottom. Shafts are less easy to maintain owing to
their smaller diameter and greater depth. In some cases the coarse material
used to fill the shaft must be replaced.
Recharge Wells
Recharge wells are used to tap deep aquifers. In many respects they are
similar to water-supply wells except water is pumped into rather than out of
them. They are cased through the material overlying the aquifer and if the
earth materials are unconsolidated, a screen is placed in the well in the zone
of injection (fig. 11). The purpose of the screen is to prevent the aquifer
from caving into the bore hole and to permit access to the water-bearing
materials. In some cases, several recharge wells may be installed in the
same bore hole (fig. 12).
When compared to other techniques of artificial recharge, injection wells
are generally both expensive to construct and to maintain. The major advantages
lie in their ability to tap deep reservoirs and the fact that space requirements
are small. Except in very permeable reservoirs their major disadvantage, other
than cost, is their tendency to become plugged by the accumulation of fine-
grained sediment in the aquifer adjacent to the well and to the buildup of
slime brought about by the action of microbes. Thus, water quality is a major
control factor in the use of wells for artificial recharge.
Injection wells are used for a variety of purposes other than for improving
water supply. These include secondary recovery of petroleum, disposal of wastes
and drainage. In a great many cases these procedures lead to ground-water
contamination.
19
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Figure 11. Recharge wells are commonly screened in the
injection zone, which may be separated from the
land surface by a considerable thickness of low
permeability strata.
20
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Casing
Jb'o. 0
Figure 12. Some recharge wells consist of several lengths of
pipe of different diameter installed one inside
the other, which permits recharging several aquifer
interbedded with confining layers.
21
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SECTION 3
SELECTED RECHARGE FACILITIES AND EXPERIMENTAL SITES
IN THE UNITED STATES
A considerable number of artificial recharge sites and experimental plots
exist in the United States. Several have been in operation many years, others
are in some stage of development, and still others have been abandoned for one
reason or another.
The operations that are briefly described in the following are but a few
examples. The selected cases represent some of the generalized techniques that
have been developed over the past several decades. The key to any successful
artificial recharge project is ingenuity—the development of an economical sys-
tem that conforms to the geology* hydrology, and availability of property.
Prior to 1959 most of the water supplies in Peoria, Illinois, were obtained
from wells. Excessive withdrawals from the sand and gravel aquifer at Peoria
resulted 1n progressive water-level declines and by tne early 1940's remedial
measures were urgently needed. The Illinois State Water Survey decided artifi-
cial recharge might provide a solution to the problem C.Suter and Harmeson, 1960).
Several artificial recharge methods were considered in detail and in 1949
a 10 m (30 ft) deep recharge pit was constructed adjacent to the Illinois River
(fig. 13), where the ground-water level averaged 6 to 7.6 m (20 to 25 ft) below
normal river elevation. Originally, a 15 cm \6 in.) layer of clean sand was
placed in the pit to serve as a filter media. Because rapid plugging of the
sand reduced Infiltration rates, it was replaced with pea gravel. A second
pit was constructed in 1956. Water flowed by gravity into the pits via a pipe
from the Illinois River with the flow being manipulated in a control tower.
The raw river water was chlorinated before It entered the pits.
The recharge rate when both pits were in operation was 1n excess of
17032 m3 (4.5 million gallons per day). The system resulted in an immediate
and substantial rise in the ground-water level, particularly near the pits.
The successful operation of the experimental recharge facility led to the
construction of similar installations at industrial sites in Peoria.
For more than a half century, Minot, a town in northcentral North Dakota,
has had occasional severe water problems ranging from periods of no stream flow
to rapidly declining ground-water levels. Water rationing has often been
involved. In 1916, the first well drilled into Minot aquifer showed there was
considerable potential for ground-water development in the valley. Reportedly,
the depth to water in 1916 was less than a meter (two feet) below land surface.
Pumping caused the water level to decline about 4 m (12 ft) by 1929, 8.5 m
(28 ft) by 1931, 14.6 m (48 ft) by 1939, and to 17.7 m (58 ft) by 1941.
22
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CONTROL TOWER
PIT
INTAKE
Top of Levee
High Woter-7
ILLINOIS
RIVER
Elev. 440.0
Gauge 11.6
[L—i
Dredge Line
16" Transite Pipe in
42" Corr. Iron Culvert
6 Sand or Pea Gravel
SAND S GRAVEL
Ground Woter Level-'?
Rock
Figure 13. The experimental recharge pit at Peoria
obtained its water supply from the Illinois
River.
23
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Mid-1952 began a wet period that lasted until late summer 1955. Discharge
of the Souris River which bisects the city and provides part of its supply,
increased substantially and the stream channel was scoured enough to permit a
large amount of infiltration. The water level recovered about 5 m (17 ft),
but the trend was again reversed during the next five years and the water level
declined an additional 6 m (20 ft) by 1960.
During the late 1950*5 city officials decided to try to solve their water-
supply problem. Several believed that a pipeline to the Missouri River, 76 km
(47 miles) to the south, would solve the problem permanently. However, an
estimated 1959 cost for this facility was about $12,000,000, which the city
could not afford. Officials then sought advice from the U.S. Geological Survey
whose hydrologists estimated that wells could produce 3785 m3 (one million
?allons) per day per 1.24 km (mile) of river flood plain in areas upstream from
he city. The cost of a ground-water system was substantially less than a pipe-
line to the Missouri River. A bond issue was passed, water rights to some 35.5
km (22 miles) of flood plain were acquired, and construction began on a major
enlargement of the water-treatment plant in anticipation of a bountiful and
readily available ground-water supply.
Drilling of pilot holes for the new well field began early 1n 1961 but it
soon became apparent that, contrary to the estimates, the aquifer was, for all
practical purposes, limited to an area within the corporation boundary. City
officials had no choice but to reevaluate the situation and drill additional
wells within the city limits in the hopes that an adequate supply could be
obtained.
Within months it became apparent that the new well field was Inadequate.
Water levels declined rapidly during the close of 1961 following the completion
of eight new city wells. By late summer 1964, the accelerated decline, largely
due to drought conditions, had caused the nonpumplng water level 1n the central
part of the well field to fall 21 m (70 ft) below land surface.
An investigation of the Minot aquifer, begun in the fall of 1963, showed
that the annual daily pumpage from the aquifer exceeded the estimated rate of
natural recharge and that it would be of little value to deepen existing wells
or to drill new ones in the same aquifer (Pettyjohn, 1967).
Four solutions to Minot's water-supply problem were suggested:
1. Construct a dam on the Souris River flood plain to Impound surface
water;
2. Construct a pipeline to the Missouri River;
3. Develop a well field in a thick but unexplored, deep aquifer about
11 km (seven miles) down valley;
4. Artificially recharge the aquifer to halt or reduce the water-
level decline.
The first three possibilities exceeded both the time and financial
resources available to the city. Consequently, 1t was decided to examine
24
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the feasibility of artificial recharge. In the fall of 1964, the potential
for artificial recharge was investigated and by winter of 1965, construction
of a recharge system was begun.
The recharge facility is contained within a pie-shaped 3 ha (7.5 acre)
parcel of land. A recharge pit, constructed at the wide end of the site, fed
into a Y-shaped canal system (fig. 14). Along the bottom of the canal were
bored thirty-six .76 m (30 in.) diameter holes that were filled with gravel.
Some months later, four large holes, about 4 m (12 ft) in diameter, were exca-
vated and backfilled with gravel. The gravel-filled shafts permit water to
infiltrate from the canals down through a layer of silt and clay into the
aquifer (fig. 15). Water supply for the recharge system was obtained from the
Sourls River, approximately 305 m (1000 ft) south of the recharge site. The
raw water was pumped directly from the river at a rate of about 15140 m3 per
day (4 mgd), the maximum rate of recharge at the site (Pettyjohn, 1968).
A small dam on the Souris River was constructed several hundred meters
downstream from the recharge site in order to deepen the water over the recharge
pump intake, to augment the surface-water supply and to Increase natural river
infiltration in the vicinity of the well field. The entire recharge facility,
including land purchase, engineering, and construction costs, amounted to approxi-
mately $106,000. The cost of the dam was an additional $87,000, and the total
cost of the entire recharge system amounted to $193,000. Annual maintenance and
cleaning costs averaged about $1,200. The cost involved in the construction of
Minot's artificial-recharge facility were small in comparison to the benefits
received, insignificant if compared with the cost of $15,000,000 (1964) for a
pipeline to the Missouri River, and infinitesimal if compared with the cost of
a surface-water reservoir with a storage capacity equal to that of the Minot
aquifer.
Several major benefits accrued from Minot's artificial recharge operation.
Of prime importance was the rapid rise in water level throughout the entire
aquifer. This rise, in places, exceeded 6 m (20 ft) after six months of oper-
ation. Future municipal withdrawals can be increased because of the large
quantity of water added to underground storage. During optimum operating con-
ditions at least 15140 m3 per day (4 mgd) were added to storage by artificial
means and at least 11355 nr per day (3 mgd) by natural infiltration from the
surface and from underflow from adjoining ground-water sources. Much of this
water previously flowed unused down the Souris River.
The greater part of the Dayton, Ohio, municipal water supply comes from
wells on and near Rohrers Island in the Mad River Valley in the northeastern
part of the city. These wells yield an average of afcdnt 151,400 m3 per day
(40 mgd); the peak pumpage 1s as hifh as 340,650 m3 per-day (90 mgd). The
supply is maintained by artificially recharging the aquifer, in what is
probably the outstanding example of proper ground-water management in this
part of the United States.
Infiltration ditches and lagoons covering a 8 ha (20 acre) area have been
dredged and are flooded periodically to recharge the underlying aquifer, Flood-
ing 1s accomplished by diverting water from the Mad River through a large intake
pipe near the head of the island. Flow through this diversion is maintained
25
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3c1
-z-z-z-z-z-z1:
"=Z"
-80
LAND SURFACE
10" WATER LINES
Teat hole
Hydraulic connector (30 inches)
MATCH LINE
Hydraulic connector ( 72 inches)
INTAKE
- PUMPING
Railroad
Figure 14. Geologic cross section and plan view of
Mi not's artificial recharge system.
26
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-Observation well
Schematic lines of flow-*
Washed-gravel
backfill
Sandy clay
^aquiclude^-
- Casing (72 inches)
-Perforations:
Sand and gravel
aquifer
r:.
Figure 15. Hydraulic connectors at Minot are large
diameter, gravel-filled shafts that
penetrate a low permeability layer and
permit direct access of the recharge
water to the aquifer.
27
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by a dam in the main channel of the river near the head of the island and by
another dam about a kilometer below the intake pipe. The purpose of the dams
is to raise the water sufficiently to cause flow into the infiltration areas.
The lagoons and ditches are dredged each year to remove the bottom material
and thus maintain a high rate of infiltration through the ponds.
During the dredging operation when the ponds are dry, water levels in the
aquifer decline 9 to 12 m (30 to 40 ft) below the land surface, but throughout
the rest of the year, when the ponds are full, ground-water levels are 3 to 4 m
(10 to 12 ft) below the surface. Methods of maintaining the recharge ponds
have changed over the years as various experiments have been made, and they
have evolved into the present system, the effectiveness of which is demonstrated
by the stability of the water supply over the past several years.
Since 1869, Kalamazoo, Michigan, has obtained its municipal water supply
exclusively from ground-water sources (Deutsch, 1967). A rapidly declining
water table and a concominant supply problem began to appear in the late 1930's
and especially in the latter part of World War II. In view of an impending
serious shortage of water, city officials began an intensive water-management
program, including the construction and use of artificial-recharge facilities.
Excavations were made in small stream channels to provide recharge ponds, and
wells were drilled around each pond to form unique recharge-discharge points.
At other sites storm water is collected 1n basins and allowed to Infiltrate
into the ground. Hew areas have been purchased for future artificial recharge
sites and well fields. These sites generally consist of small basins drained
by perennial streams. Systematic drilling and testing programs are conducted
and test vyells that show high yield potential are made into production wells
and capped for later use. Sand and gravel along the streams have been dredged,
in places, forming recharge basins, the excavated material sold, and the
surrounding area developed into parks.
At one of the sites, artificial recharge is accomplished by inducing what
is called Interaquifter leakage. The glacial deposits at this particular site
consist of a thick valley fill sequence of sand and gravel overlain by about
12 m (40 ft) of silt and clay, which in turn is covered by about 30.5 m (100
ft) of permeable sand. The surficlal sand forms an aquifer that is 1n direct
hydraulic connection with Portage Creek, a small stream that drains it.
Under natural conditions the water-pressure surface 1n the lower aquifer is
higher than the water table in the upper sand, and leakage through the fine-
grained material ts upward (fig. 16). Pumping from the lower aquifer reversed
the direction of leakafe but sustained puftping would have resulted 1n objection-
able declines in the deeper water-pressure surface with attendant Increases in
pumping lift and probable Inflow of poor quality water from below.
An irregularly shaped recharge channel was constructed adjacent to Portage
Creek. Water 1s diverted from the stream to the channel and maintained at a
constant level. When water is pumped from the deep aquifer, surface water In-
filtrates from the recharge channel into the shallow aquifer, through the fine-
grained material and into the deeper aquifer (fig. 16). After six years of
pumping at the well field under recharge conditions water levels were essen-
tially the same as they were at the time the original recharge tests were
28
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West Fork Water table
Water-pressure surface
Portage Creek
Lower aquifer
-
Under natural conditions, water from the lower aquifer leaked upward
through the confining bed to the shallow aquifer and eventually into
Portage Creek.
Water-
Water table
When the lower aquifer was pumped, water migrated from the recharge
channel to the upper aquifer and then through the confining layer to
the lower aquifer permitting higher sustained well yields.
Figure 16. Diagrammatic sketch of the hydrogeological conditions
at an artificial recharge site in Kalamazoo, Michigan.
29
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conducted. The quantity of water recharged to the lower aquifer has been at
least equal to the amount pumped.
Valley City, North Dakota, had a population of 5,000 in 1930, and about
8,000 in 1960, but during the same interval water use increased nearly J™e
times. Artificial recharge has been practiced at Valley City since 1932. Since
that time water has been diverted through a kilometer long ^OTJ£fnrt
Sheyenne River to an abandoned gravel pit on the adjacent
the early use of this recharge system the ground-water level was *J®1sed more
than .7 m (22 ft) and a large source of water was provided at a moderate price
even during drought seasons. Not only has much water been st°red for later
use, gradual improvement in its chemical quality has occurred because water
from the Sheyenne River is less mineralized than the native ground water.
An unusual ground-water recharge system was developed at Canton, Ohio, in
the late 1940's. Trending through the northwestern part of the city is a buried
glacial river valley, about a kilometer (3,000 ft) wide, that contains as much
as 46 m (150 ft) of sand and gravel in the lower part. *his,?3uJfer
is a layer of tight plastic clay that in turn is covered by 6 to 1Z m (Z0 to
40 ft) of sand and gravel that forms a surficial aquifer. The West Branch of
Nimishillen Creek crosses the buried valley and part of the flow in the stream
is derived from water discharging from the shallow aquifer.
Water pumped from wells tapping the upper aquifer and adjacent to the stream
would be replaced by induced infiltration as long as there was water in the
stream. Since the upper aquifer is thin, the usable quantity of water in stor-
age was inadequate to fulfill the water supply needs in that &rn. I ® :eefe!*i
thicker aquifer was already overdeveloped and received only a limited amount of
natural recharge. It was decided that;.the solution to the problem lay in find-
ing a method of utilising the upper thin aquifer to filter sediment and micro-
organisms ftw the wa|$$Kthen connecting it to the lower aquifer, which could
serve as a major j&tfre&of supply. Three large diameter collector wells were
constructed, each of which, was completed in both aquifers (Kazmann, 1965).
Concrete caissons* approximately 4.6 m (15 ft) 1n diameter, were sunk to the
bottom of the deeper aquifer. A concrete plug was poured to seal the bottom of
the caisson and then slotted steel pipes were jacked horizontally out of the
caisson into the aauifers. The slotted laterals, resembling the spokes of a
wheel, were injected in both the upper and lower aquifers. This particular
arrangement permitted water to infiltrate from the stream to the shallow aquifer
where it was 1nter8®p*asrd by the upper tier of laterals. The water then cascaded
down the collector and flowed out the lower tier of laterals, recharging the
deeper aquifer (fig. 17).
The Canton recharge well was placed In operation In 1948 and permitted an
average pumping rate from the deeper aquifer of approximately 22710 m3 per day
(6 mgd). Between 1949 and 1961 there was no substantial change 1n the ground-
water levels in the area.
At Fresno, California, investigations are being conducted involving the use
of agricultural surface water for artificial recharge to augment an urban ground-
water supply- This study, known as the Leaky Acres project, Involves the use of
10 ponds into which are diverted irrigation waters, which infiltrate to the
aquifer and become part of the ground-water supply.
30
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STREAM LEVEL
.SANb'ANb GftAVEL
IMPERVIOUS CLAY
..WATER LEVEL
LOWER AQUIFER
SAND AND GR aVIlL:
Figure 17. A large-diameter collector well at Canton, Ohio
captures water from a stream and shallow aquifer
and directs it through a series of laterals
extending from the bottom of the caisson in order
to recharge a deeper, heavily pumped aquifer.
31
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The 10 basins forming Leaky Acres contain 47.4 ponded hectares (117 acres)
for waterspreading. The recharge facility is situated on an alluvial fan. The
fan deposits are very heterogeneous, both vertically and horizontally (Nightingale
and Bianchi, 1973).
Prior to ground-water recharge the chemical quality beneath Leaky Acres
had an average electrical conductivity of approximately 140 ymhos/cm. The
water used for recharge, which is obtained from the Kings River via the Gould
Canal, has a low mineral content. The conductivity of the canal water ranges
from highs of 100-200 ymhos/cm during the rainy season of December through
February to lows of 30-40 ymhos/cm during the summer when snowmelt is released
from mountain reservoirs for irrigation. Recharge at Leaky Acres has noticeably
decreased the ground-water salinity for a distance of about two kilometers in
the direction of regional ground-water movement. During numerous recharge
¦periods spanning the years from 1971 to 1975, more than 65.86 million cubic
meters (17.388 billion gallons) of water infiltrated to the underlying aquifer.
When fully operational with 47.4 ha (117 acres) of ponds and 300 days of re-
charge per year, this project could supply 15-25% of the current amount of
ground water pumped by the city water division.
An unusual increase in the turbidity of well water in the vicinity of the
Leaky Acres recharge area was reported by Nightingale and Bianchi (1977). Water
of low turbidity and dissolved solids content was pumped Into spreading basins.
After six months of recharging, ground-water salinity decreased from a mean of
147 to about 100 ymhos/cm but the ground water became turbid. With continued
recharging, salinity decreased to an average of 74 ymhos/cm, but turbidity
increased more than tenfold under the site. Outside the area, however, tur-
bidity again decreased.
The increase in turbidity was related to poorly crystallized and extremely
fine colloids that were leached from the surface soils because of the low
dissolved solids cogent of the recharge water. Although economically unfeasi-
ble, gypsum applications would have reduced this phenomenon. The turbidity
increase was short lived, however, and presented no significant long term
problem. On the other hand, reactions such as these could possibly reduce the
permeability of a recharge facility.
Salt water originating from San Francisco Bay in the vicinity of Palo Alto,
California, is contaminating a near shore multiple aquifer system (Sheahan, 1977).
A salt-water Intrusion barrier 1s being constructed to reduce the potential of
contamination of the ground-water supplies in this area. The salt-water intrusion
barrier will consist of a series of Injection wells that will recharge 7570 m3
per day (2 mgd) of reclaimed wastewater into'a shallow aquifer. The recharged
wastewater will be removed by a similar series of extraction wells 1n order to
avoid possible degradation of the aquifer and to allow reuse of the reclaimed
water (fig. 18)-.
The three aquifers that occur within the area at depths of 6, 14 and 56 m
(2, 45 and 185 ft) below land surface are separated by strata of low permeability.
The injection/extraction wells are double cased and double screened, with neat
cement grouting separating the two shallower aquifers. All three wells are
installed in a 61 cm (24 in.) diameter drilled hole.
32
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EXTRACTION
WELL
INJECTION
WELL
RECLAIMED WATER
I-original Hydraulic->---
gb apj e
SAN FRANCISCO
BAY
V_
^Mv^dfECTED'^:^:J
-INJECTION
BARRIER
Figure 18. Diagrammatic illustration of operation of
injection/extraction doublet (modified from
Sheahan, 1977, p. 44).
33
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In conjunction with the artificial recharge experiments at Palo Alto, other
investigators are studying the transport and fate of organic compounds that occur
in the injected wastewater (Rittmann and others, 1980). It is recognized that
the use of reclaimed wastewater for direct recharge of aquifers provides the
probability of introducing residual pollutants directly into the ground water.
Questions concerning the fate and transport of organic substances in the sub-
surface are important in attempting to assess the risks that hazardous pollutants
may provide to sources of water supply. Field studies, for example, indicate that
some organic pollutants, such as naphthalene and heptaldehyde are biodegraded,
while other compounds, such as chloroform and chlorobenzene are not. The latter,
however, are affected to some extent by adsorption and the concentration of still
others is reduced both by biodegradation and absorption. The movement of in-
organic contaminants is affected by ion-exchange, adsorption and precipitation.
A similar salt-water intrusion barrier was developed at the Manhattan Beach,
California, recharge project in 1951. In this case nine 30.5 cm (12 in.) diam-
eter wells were drilled at 152 m (500 ft) intervals to form a line near and
parallel to the coast. The wells penetrated an artisian aquifer about 33.5 m
(110 ft) thick, the top of which was about 30.5 m (100 ft) below land surface.
Using treated water from the Colorado River, recharging began early in 1953.
The water was chlorinated in order to prevent the formation of slime-forming
bacteria in and around the well.
A series of artificial recharge experiments on Long Island, New York, were
conducted by the U.S. Geological Survey for a number of years beginning 1n the
1960's. The purpose of the experiments was to evaluate the feasibility of In-
jecting highly treated sewage plant effluent into a network of barrier Injection
wells with the Intention to prevent or retard the landward movement of salty
water from the Atlantic Ocean into major aquifers beneath Long Island (Cohen
and Durfor, 1967). The experimental injection well, which 1s about 152 m
(500 ft) deep, consists of two adjacent fiberglass casings with stainless
steel screens that tap the Magothy aquifer.
The aquifer was recharged with tertiary treated sewage during a research
phase between 1968 and 1973. The reclaimed water was Injected Into very fine to
medium sand, which contained some silt and clay. Clay In the aquifer consists
of equal parts of kaolinlte and illite. Particles and layers of lignite are
also present, as are pyrite and marcaslte. Dissolved sol Ids content of the
native water in the Magothy ranged between 22 and 25 mg/1, while that of the
reclaimed water had a mean concentration of 398 mg/1 (Ragone and Vecchloll, 1975).
During recharge a number of reactions occurred within the aquifer that
resulted 1n a degradation in water quality with respect to Iron concentrations
and pH. Iron concentrations in the water Increased from a 0.14 to 0.30 mg/1
range to as much as 3 mg/1 (recommended limit 1s .3 mg/1) as reclaimed water
replaced native water. Presumably the Increase was due to the dissolution of
pyrite and marcaslte. The pH of the water decreased from a native 5.22 to 5.72
range to a low of about 4.50. Iron concentrations increased and the pH de-
creased with increasing distances from the recharge well. A common problem
with this recharge system was the continual clogging of the screen with
bacterial slime and sediment.
34
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The U.S. Marine Corps base at Camp Pendleton has been operating an exten-
sive water program since 1943 (Schmidt and Clements, 1977). The water supply
for the base is obtained from four deep ground-water basins. The basins are
continuously recharged with reclaimed effluent, surface runoff, and precipita-
tion. Recharge in the Santa Margarita River basin is accomplished by on-
channel water spreading structures, off-channel water spreading structures,
recycling of sewage effluent, phreatophyte control, and erosion reduction
structures (fig. 19). During the rainy season water from the Santa Margarita
River is diverted either Into Lake O'Neill or to off-channel spreading basins
that have very high infiltration rates. The lake serves as a storage reser-
voir. Nine on-channel water spreading structures lie on the riverbed below
Lake O'Neill. The waters spread out forming shallow lakes behind a series of
low levees that cross the channel. Effluent from five sewage treatment plants
is used to recharge the basins and to maintain a salt-water intrusion barrier.
The total cost for the recharge operation in 1972 amounted to $15 per 3785 m2
(million gallons).
The Hemet-San Jacinto ground-water basin is an important source of irriga-
tion and drinking water for the local area (Schmidt and Clements, 1977). In
July, 1965, the Eastern Municipal Water District completed the construction of
a new sewage treatment plant. Shortly thereafter the U.S. Environmental Pro-
tection Agency provided funds for a project to demonstrate the feasibility of
recharging the ground-water basins with treated secondary effluent. Since that
time, treated wastewater has been spread in recharge basins, both as a method
of disposal and for replenishing the ground water.
The recharge area consists of 10 ponds covering an area of approximately
6.5 ha (16 acres). The ponds are arranged in two parallel groups and the
reclaimed water can be diverted into any combination of ponds. The basins are
interconnected with overflow gates to allow transfer of water from one basin
to another. Each basin requires about one day to fill and two days to drain.
The pond is then permitted to dry for at least one day in order to reduce algal
growths, which reduce the rate of infiltration. The basins are periodically
rototilled. In 1972 the total cost for the recharge system, including equip-
ment amortization and overhead, amounted to $22,100 per year for an average
flow of 7570 m3 per day (2 mgd), or approximately $30 per 3785 m2 (million
gallons).
In 1967, an experimental high rate land application system, called the
Flushing Meadows project, was installed in the bed of the Salt River west of
Phoenix, Arizona (Schmidt and Clements, 1977). The purpose of the project was
to study the feasibility of renovating secondary effluent from unrestricted
irrigation, recreation, and certain industrial uses. The recharge system con-
sists of six basins 6 m (20 ft) wide and 213 m (700 ft) long spaced 6 m (20 ft)
apart (fig. 20). Secondary effluent is pumped from a channel into the basins.
Gravel dams were placed across the basins, about 15 m (50 ft) from the inlets,
to form sedimentation basins. Because of the successful experiments at Flushing
Meadows, the City of Phoenix has completed construction of a 56775 m3 per day
(15 mgd) wastewater recharge/extraction facility. The project is a first step
toward extensive wastewater renovation and reuse.
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ii; SANTA MARGARITA
$1 RIVER
Hi (UNDERGROUND
HI MOST OF YEAR)
OFF
CHANNEL
SPREADING
GROUNDS
OXIDATION
POND
TREATMENT
PLANT
TREATMENT
PLANT
ON
OXIDATION
POND
FALLBROOK
CREEK
(1.4 MGD OF
SECONDARY
EFFLUENT)
TREATMENT
PLANT
TREATMENT
PLANT
SPREADING
GROUNDS
COASTLINE
ON-CHANNEL
DIVERSI
DAM
DYKES
POND
GOLF
COURSE
IRRIGATION
SPREADING
FOR SALT
INTRUSION
GROUNDS
WATER
BARRIER
OXI-
DATION
PONDS
Figure 19. Schematic of the ground-water recharge system
at Camp Pendleton, California.
36
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CO
¦vl
BASE NO
SUPPLY LINC
f=
•RAVEL DAM
=1
CONSTANT - HEAD
STRUCTURE
— DRAINAGE LINE
I U- LINED
I I PONDS
-0—UN LINED PONO
-O-^EAST WELL
100 METERS
300 PEET
Figure 20, Plan view of the Flushing Meadows artificial recharge facility
at Phoenix, Arizona.
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The village of Glenburn in north-central North Dakota had a difficult time
supplying sufficient water for their needs. They overcame this problem with an
unusual and inexpensive artificial-recharge technique. Most of the surficial
rocks in the Glenburn area consist of clay but nearby there is a 9 m (30 ft)
wide gravel-filled stream channel, usually dry, that contains about 2 in (7 to
8 ft) of coarse gravel and sand. Upstream the deposit widens and here there
is an abandoned gravel pit.
During the spring runoff period a considerable amount of water infiltrates
the gravel and the water table rises rather dramatically. Because the deposits
are very permeable, the ground water flows down gradient quickly, however, and
the water table soon declines. Thus the gravel channel has a considerable
capacity for storage but no natural controls to prohibit rapid drainage.
This problem was solved by excavating a ditch, a meter or two (4 or 5 ft)
wide, across the channel and entirely through the gravel deposit. The excavation
was backfilled with readily available clay forming a subsurface dam (fig. 21).
A perforated culvert, serving as a well, was installed on the upstream side.
A diversion ditch was excavated from the intermittent stream to the abandoned
gravel pit,,which served as a recharge basin. During periods of runoff, some
of the surface water flowed into the gravel pit, where it infiltrated and part
of the remainder infiltrated along the stream bottom. Thus, during wet periods
a considerable amount of water collected in the underground storage reservoir.
The subsurface dam impeded the flow of the ground water down the gravel-filled
channel and the water table remained at a high level, permitting increased water
usage.
Artificial recharge can also be used to renovate contaminated aquifers.
Waste disposal lagoons at a chemical plant contaminated the ground water so
seriously that operations had to be reduced due to a scarcity of make up water
of adequate quality. Induced infiltration from a major river served as the
supply. The supply source was a large diameter collector well with several
hundred meters of horizontal laterals radiating outward from the cassion.
Pumping not only induced infiltration from the river, but also caused the
contaminants to flow to the well.
The recharge system design called for a U-shaped canal, extending inland
from the river, surrounding the collector well laterals, and returning to the
river (fig. 22). Eighteen large dJameter gravel filled recharge shafts were to
penetrate fine-grained rtaterial separating the bottom of the canal from the
aquifer. Water would flow from the river through the canal, some would infil-
trate through the shafts to the aquifer, and the remainder would discharge,
downstream, into the river. The purpose of the recharge systems was to form
a ground-water moufld in the aquifer separating the well from the source of con-
tamination. This would cause the polluted ground water to slowly discharge into
the river instead of the well. The entire water supply derived from the well
would eventually owe its origin to induced infiltration from the river and
artificial recharge. The chemical quality of the well water would closely
resemble the quality of the river.
Water supply problems in arid regions are particularly vexing because of
scanty rainfall and the high rate of evaporation. In some situations, it may
38
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Figure 21. A subsurface dam of clay impeded the flow of ground
water in a pond and gravel-filled channel in the
vicinity of Glenburn, North Dakota.
39
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Proposed canal and shaft*
Disposal
Pond
/°
\o
\ Dirsction of
contaminant flow
River
Canal and Disposal
shaft -j pond -7
Figure 22. Proposed artificial recharge system to improve
ground-water quality at an industrial complex.
40
k
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be possible to augment supplies not only bv artificial
constructing artificial aquifers. Artificial aoijJfpJl r®char9e but also by
only moderate quantities of water, but they are labn£ n?cessity» can store
can be built at a modest equipment cost. '"tensive and, therefore,
Ind1aI1e»^ descH^t^^ " Clara
small gulley, several meters Wide: warc^ared of vLlta??nnS,nlth (19,78)* A
sloped. Spoil material was used to construct an earthM Hm' deepene?» and
A trench was cut adjacent to and parallel with the dam in*?1 J?ruSS 9ulley.
slotted plastic pipe. The slotted £?pe «s conJ«t£ It * ,nsta,,ed
second pipe, extending through the dam in the low oolnt ofif"9 • t0 a
second or discharge pipe was laid on a slight dolsloSe The
Installed prior to dam construction. aownslope grade (fig. 23) and
Once the guTley was shaped, the pioes installed anw u
lining was placed on the floor of the structure The nuiiou ^ 2 plastic
with uniform sand (gravel cduld be used) and tonnea nil ulth then backfilled
completing the artificial aquifer. ' • t°PP8d °" w1th flravel mu,ch- thus
During the rainy season or periods of surface runoff wate* j
the gulley and infiltrated through the gravel mulch to tte "tific^lulftr
In some cases, 1t might be necessary Jto construct a soillwav tn «
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Figure 23. Schematic of an artificial aquifer.
42
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REFERENCES CITED
Bianchi, W. C. and D. C. Muckel. 1970. Ground-Water Recharge Hydrology.
U.S. Dept. Agriculture, ARS 41-161, 62 pp.
Cohen, Philip and C. N. Durfor. 1967. Artificial Recharge Experiments
Utilizing Renovated Sewage-Plant Effluent: A Feasibility Study at Bay
Park, New York, U.S.A. International Assoc. Sci. Hydrology, Symposium
of Haifa, pp. 193-199.
Duetsch, Morris. 1967. Artificial Recharge by Induced Interaquifer Leakage.
International Assoc. Sci. Hydrology, Symposium of Haifa, pp. 159-172.
Helweg, 0. J. and George Smith. 1978. Appropriate Technology for Artificial
Aquifers. Ground Water, 16(3):144-148.
Kazmann, R. G. 1965. Modern Hydrology. Harper and Row, New York, pp. 171-176.
Nightingale, H. I. and W. C. Bianchi. 1973. Ground-Water Recharge for Urban
Use. Ground Water, 11(6):36-43.
Nightingale, H. I. and W. C. Bianchi. 1977. Ground-Water Turbidity Resulting
from Artificial Recharge. Ground Water, 15(2):146-152.
Pettyjohn, W. A. 1967. Geohydrology of the Souris River Valley in the Vicinity
of Minot, North Dakota. U.S. Geol. Survey, Water-Supply Paper 1844, 53 pp.
Pettyjohn, W. A. 1968. Design and Construction of a Dual Recharge System at
Minot, North Dakota. Ground Water, 6(4):4-8.
Ragone, S. E. and John Vecchioli. 1975. Chemical Interaction During Deep Well
Recharge, Bay Park, New York. Ground Water, 13(1):17-23.
Rittmann, B. E., P. L. McCarty and P. V. Roberts. 1980. Trace-Organics
Biodegradation in Aquifer Recharge. Ground Water, 18(3):236-243.
Saines, Marvin. 1974. Ground Water 1n the News. Ground Water, 12(4):249-250.
Schmidt, C. J. and E. V. Clements. 1977. Reuse of Municipal Wastewater for
Groundwater Recharge. U.S. Environ. Protect. Agency, EPA-600/2-77-183,
183 pp.
Sheahan, N. T. 1977. Injection/Extraction Well System—A Unique Seawater
Intrusion Barrier. Ground Water, 15(1):32-49.
43
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Suter, Max and R. H. Harmeson. 1960. Artificial Ground-Water Recharge at
Peoria, Illinois. 111. State Water Survey, Bull. 48, 48 pp.
Thomas, H. E. and D. A. Phoenix. 1976. Summary Appraisals of the Nation's
Ground-Water Resources—California Region. U.S. Geol. Survey, Prof.
Paper 813-E, 51 pp.
Todd, D. K. 1959. Ground Water Hydrology. John Wiley & Sons, New York, 336
United Nations. 1975. Ground-Water Storage and Artificial Recharge. Dept.
Econ. and Social Affairs, Natural Resources/Water Series No. 2,
ST/ESA/13, 270 pp.
44
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