Title: Ground Water Issues and Answers
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Title: Ground Water Issues and Answers
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Language: English
Publisher: American Institute of Professional Geologists
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Spatial Coverage: North America -- United States of America -- Florida
 Notes
Abstract: Ground Water Issues and Answers American Institute of Professional Geologists
General Note: Box 7, Folder 4 ( Vail Conference 1989 - 1989 ), Item 91
Funding: Digitized by the Legal Technology Institute in the Levin College of Law at the University of Florida.
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Volume ID: VID00001
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.......












Foreword

The American Institute of Professional Geologists (AIPG) is a nationwide
organization of 4,700 members representing all areas of specialization in the
professional practice of geology. The Institute serves both the profession and
the public through its certification program and its involvement in public affairs.
One form of AIPG involvement in public concerns is publication of "issue papers"
such as this one, dealing with current specific matters in which geology is signifi-
cant to formulating prudent public policy, legislation, or governmental regulation.

Ground water is a most important natural resource, currently the focus of
considerable public interest. Wise development, management, and protection
requires fundamental knowledge of ground water and its problems. The purpose
of this booklet is to provide policy makers, legislators, and the general public with
information and data to better understand U. S. ground-water resources both
their potential and limitations so that they can be managed in the best long-
term interest of the Nation.

We hope this booklet serves that purpose. If you have questions or com-
ments, or if you would like additional copies, please contact:


AIP AMERICAN INSTITUTE OF PROFESSIONAL GEOLOGISTS
7828 Vance Drive / Suite 103, Arvada, Colorado 80003
303 / 431-0831


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Contents


What is Ground Water? ........................................ 2
Aquifers Store and Transmit Ground Water .......... 4
Natural Quality of Ground Water ............................ 6
Ground Water Resources in Geologic Regions ...... 8
Where Ground-Water Use is Concentrated ............. 10
Ground Water Serves Many Users .......................... 11
Major Ground-Water Problems: .............................. 12
Overdraft / Regional, Local .......................... 12, 13
Legal / Law, Rights, Ownership .......................... 14


Contamination / Principal Sources .................... 16
Industrial and Underground .................... 17
M municipal ............................ ................... 18
Agricultural and Domestic ....................... 19
Liquid W aste ........................-................... 20
Information Required for Decision-Making .............. 21
Role of Ground Water in Planning, Decision-Making 22
AIPG Policy on Key Ground-Water Issues ...... 22, 23
G lossary ..-................................. ..................... 24
References .....-----................................. Inside Back Cover


This publication may be reproduced for educational purposes, without charge, provided that acknowledgement is given
to the American Institute of Professional Geologists. Additional copies are available from the Institute at $3.00 postpaid.


0










What Is Ground Water?


Many people think of ground water as under-
ground lakes or streams. There are such things in
areas of cavernous limestones or volcanic lava flows -
but mostly, ground water is simply water filling spaces
between rock grains or in cracks and crevices in rocks.
Such openings are most common near the land
surface; at great depth openings are closed by the
great pressure of overlying materials.
Rain and snowmelt percolating down through the
soil are the source of ground water. Plants consume
much of the water that enters the soil, and a small
amount is held on the soil grains by capillary forces;
any surplus percolates downward to the zone of
saturation. The top of the zone of saturation is called
the water table. At this level, pressure is the same as
that of the atmosphere, or roughly 15 pounds per
square inch. Below the water table all openings are
water-filled, and the pressure at any point is determined
by atmospheric pressure, plus the weight of water
between there and the water table.
Ground water is usually in motion, flowing under
the force of gravity to lower areas where it may dis-
charge as a spring, or to a stream, or to the ocean.
The rate of ground-water flow is determined by the
hydraulic gradient (the slope of the water table or the
pressure surface) and the permeability (ease of con-
ducting water).
The amount of water a rock can contain depends
upon its porosity the ratio of open space to total
volume. In productive aquifers (water-bearing rock


layers) that are granular, such as sand and gravel,
this ratio generally is 30 to 40%. However, in crystal-
line igneous rocks and tightly cemented sedimentary
rocks, where cracks represent the only open spaces,
the porosity commonly is only 1% or less.
If water is to move freely through a rock, the
openings must be interconnected, and the openings
must be large enough so that wall friction does not
greatly impede its flow. If a rock has many connected
openings of a size sufficient to permit water to move
freely, the rock is termed permeable. Large volumes
of water can be pumped from permeable materials.
Even crystalline rocks with no intergranular spaces,
such as granite, may be permeable if broken by
crevices of sufficient size to permit water to pass freely.
Clay and similar fine-grained materials, ironically, have
high porosity, but yield water very slowly, because
their pores are so small that wall friction greatly im-
pedes water movement.
Rocks containing large openings, such as solution
channels in limestones and lava tubes in volcanic flows,
may have low overall porosity, but can have very high
permeability because the large size of the openings
permits water to flow at high velocity.
Ground water does not occur downward all the
way to the core of the earth. Beneath water-bearing
rocks everywhere, at some depth, the rocks are
water-tight. This depth may be a few hundred feet,
or more than likely tens of thousands of feet.
*Technical terms are defined in the Glossary, page 24.


ne


MAIN TYPES OF POROSITY

Ground water fills the spaces between sand grains, in rock crevices, and in solution openings.

Sand and Gravel Igneous Rocks Limesto








INTERGRANULAR CREVICE SOLUTI
(After USGS Water Supply Paper 489, Figure 1)


r


N









THE HYDROLOGIC CYCLE __

I Ground water is the fraction of precipitation that reaches the zone
of saturation after seeping through the soil or through stream beds.




SRanClouds Cloud Formation













WATER TABLE "" .
ZONE OFRECIPITATIO












Ground water moves under the force of gravity from higher elevations to lower elevations;
the rate of movement can range from several feet per day to as little as inches per century.
(After the Hydrologic Cycle, Yearbook of Agriculture, U. S. Department of Agriculture, 1955)

HOW GROUND WATER OCCURS IN ROCKS

The water table marks the top of the zone of saturation. Its level can rise or fall,
depending upon the rate of water entering and leaving the ground.

"Rings" of capillary water
Air (not ground water) Air
surround contacts of
rock particles




S Approximate _
level of the water table


All openings below the
water table are full of
ground water



GRAVEL CREVICED ROCK
(From USGS, A Primer on Ground Water)









Aquifers Store and

Transmit Ground Water


An aquifer is a rock layer that will yield sufficient
water to serve as a water supply for some use. It may be
a few feet or hundreds of feet thick. It may be just be-
neath the surface, or hundreds of feet down. It may
underlie a few acres, or thousands of square miles.
Aquifers function in two very important ways: (1)
they transmit ground water from the point of entry to
points of discharge, and (2) they provide storage for
large volumes of water. In a sense, they act as both
pipes and storage tanks. Aquifers are classified intc
two principal types unconfined and confined.

Unconfined aquifers are those in which atmos
pheric pressure changes are freely transmitted
downward through an unsaturated zone of soil or roc
to the water table. Unconfined aquifers provide watei
to wells by draining the materials surrounding the well
When the water table rises or falls, the change ir
storage is equivalent to the volume of pore space
saturated or drained.

Confined or artesian aquifers are those overlaid
by impermeable rock layers that prevent free move
ment of air and water. Thus the water is confined under
pressure, as in a pipe system. Drilling a well into
confined aquifer is analogous to puncturing a water
pipe, with water under pressure gushing into the wel
sometimes even rising to the surface and overflowing
Confined aquifers yield water due to compressio
of the aquifer materials, expansion of the watei
drainage of adjacent unconfined rock zones, and leak
confining rock layers. The "Cone of Pressure Decline
(see figure) expands rapidly over a wide area an,
recovers quickly when pumping stops. Recharge is b
subsurface flow from adjacent unconfined rock zone
and by slow leakage from and through confining roc
layers.
Because decline of water levels is a pressure
response to water withdrawal, the storage in confine
aquifers is small compared to that of unconfine
systems. However, when the pressure level decline
below the top of the aquifer, the aquifer become
temporarily unconfined, and drainage of the material
near the well occurs.


r
















AQUIFERS

Aquifers consist of
permeable rocks or
granular deposits that
transmit water freely.
They function both as
conduits and as under-
ground storage reservoirs.


I


Recl
art<
#'1


charge area for Artesian well Water-pressure level
esian aquifer (potentiometric surface)
Sof artesian aquifer
---Water-table well


Flowing
-. .artesian well
---

SStream


-- -- -- --- -

Per



(After Ground Water and Wells, UOP Johnson Div., 1966)


UNCONFINED AQUIFER


Where atmospheric pressure is freely
communicated to the zone of saturation,
the aquifer is called "unconfined."
Unconfined aquifers yield water by drainage
of materials near the well. Wells produce
water by lowering the water level, causing
water to flow radially toward the well.


CONFINED ("ARTESIAN") AQUIFER

Where an impermeable layer, such as clay,
Ground Surface above the aquifer prevents free movement
final Pressure Level of air and water, the aquifer is called
_--- '- "confined" or "artesian." Confined aquifers
meable Cay Confining Bed yield water by compression of the aquifer,
Expansion of the water, drainage of adjacent
esse Ciil unconfined zones, and leakage through
." confining layers.
S .. ." .. '."-; .


Re


Rain Recharge


Pumping
-i Well
-1 We -Ground Surface

,-Water Table
:.-Cof :e of Drawdowt :

,*^^ ..;., NIOJFINED A.QiJER :-


< ImCc


i


"









Natural Quality of Ground Water


Ground water nearly always contains more
mineral matter than nearby surface waters, although
both originate as precipitation. The main reason for
this is that water passing through the soil dissolves large
amounts of carbon dioxide formed by soil bacteria, pro-
ducing a weak carbonic-acid solution that attacks
carbonate and silicate minerals of calcium, magnesium,
and sodium, causing their solution. Where soluble
chloride and sulfate compounds are present, as in
arid climates, they are also dissolved in the infiltrating
water.
Far below the water table, relatively little additional
solution occurs. However, other chemical reactions,
such as cation exchange and sulfate reduction, may
result in substitution of one constituent for another.
But the total dissolved-solids content does not change
significantly.
In cation exchange, the ground water generally
loses calcium and magnesium, gaining an equivalent
amount of sodium in a natural "water-softening"
process. In sulfate reduction, bacteria which consume
sulfate in their life cycle add an equivalent amount of bi-
carbonate to the ground water.


In regard to quality, ground water has both
advantages and disadvantages compared to surface
water:
Advantages
* Passage through soil and sediments results in filtra-
tion of particulate matter, and adsorption of organic
compounds and some metals on clay minerals.
* Relatively constant temperature and quality.
* Relatively safe from some types of pollution, especi-
ally by airborne contaminants.
* Spread of pollution is slow.
* Sediment content is generally negligible.
M Supply is somewhat less dependent on weather
variations, compared to surface water.

Disadvantages
M Dissolved solids and hardness are higher than in
nearby streams.
* Once polluted, cleanup is slow and difficult.


QUALITY DETERMINES USABILI


Domestic -
Water for domestic use should taste and smell
good, be free from constituents harmful to health,
and should not damage plumbing or appliances.
Industrial -
Requirements for industry vary greatly depending
upon process, but generally the water should not
be highly corrosive or cause precipitates that
would clog equipment.
Irrigation -
Plants are generally tolerant of a wide range of
water quality. They are very sensitive to boron, a
plant poison, and are sensitive to dissolved solids,
which at high levels make the water unusable.
The balance between sodium and calcium is impor-
tant in maintaining proper soil structure.


(From USGS, A Primer On Ground Water)


P























































(After USGS Water Supply Paper 1469)


Water is an active solvent.


Gases, mainly carbon dioxide dissolved
from the air and in the soil, form a weak
solution of carbonic acid that attacks
mineral grains, causing further solution.









Ground Water Resources in

Geologic Regions


1. Western Mountains -Underlain by hard, dense
rocks; weathered rock locally yields modest sup-
plies, as does alluvium in intermontane valleys.
Large supplies are rare.

2. Alluvial Basins Large depressed areas flanked
by highlands and filled with erosional debris. Allu-
vial fill functions as an ideal aquifer, absorbing
water readily from streams issuing from highlands
and yielding large supplies to wells. Supports large-
scale irrigated agriculture and provides municipal
water for many cities.
3. Columbia Lava Plateau Underlain by thou-
sands of feet of basaltic lava flows, interbedded
with alluvial and lake sediments. Lava rocks are
highly permeable because of lava tubes, shrinkage
cracks, and interflow rubble zones. Yields large
supplies of water for irrigation and municipal use.
4. Colorado Plateaus and Wyoming Basins -
Underlain by gently dipping sediments, mainly
poorly-permeable sandstone and shale. Most pro-
ductive aquifers are sandstone, furnishing small
supplies for stock and domestic use. Prospects
poor for large-scale ground-water developments,
but such supplies are found at a few favorable
localities.


5. High Plains Underlain by alluvium of the Ogal-
lala Formation, as much as 450 feet thick, which
yields large supplies to wells, mainly for irrigation.
Opportunity for recharge from streams is small,
due to low rainfall and because large streams have
cut below the base of alluvium. Water table is grad-
ually declining in much of the area due to overdraft.
6. Unglaciated Central Region Complex area of
plains and plateaus, underlain by consolidated sedi-
mentary rocks. Alluvium of stream valleys pro-
vides large supplies for industry and cities. Most
productive aquifers in much of the region are dol-
omitic limestones and sandstones of low-to-mod-
erate yield.
7. Glaciated Central Region -Similar to Ungla-
ciated Central Region, except that area is mantled
by glacial deposits as much as 900 feet thick.
These contain lenses and beds of well-sorted sand
and gravel, which yield large supplies of water
for industrial and municipal use.
8. Unglaciated Appalachians Mountainous area
underlain mainly by consolidated sedimentary
rocks of small-to-moderate water yield. Locally,
limestones yield large supplies of water.
9. Glaciated Appalachians -Glacial deposits man-
tle steep areas and underlie valleys and lowlands.
Yields from bedrocks are generally small to mod-
erate. Principal ground-water sources are sand
and gravel of glacial outwash plains, or channel
fillings in stratified drift.
10. Atlantic and Gulf Coastal Plains A huge, sea-
ward-thickening wedge of sedimentary rocks con-
sisting mainly of clay, sand, marl, and limestone.
Thickness along coast increases southward from
300 to 30,000 feet. Large supplies of ground water
can be obtained almost anywhere, although salt-
water encroachment is a problem locally.
Alaska Most has been glaciated, and large sup-
plies of ground water can be obtained from glacial
sand and gravel. Permafrost is present in northern
Alaska, restricting the availability of ground water.
Hawaii--Entire island chain is composed of
basaltic lava flows, which are highly permeable and
yield water readily to wells and tunnels. Fresh-
water body forms a lens floating upon sea water,
so extraction must be carefully managed to avoid
sea-water intrusion.


1111










* GROUND-WATER RESOURCES


Numbers indicate major regions
described on opposite page.


Watercourses related to aquifers

Areas of extensive aquifers that yield more
than 50 gallons per minute of fresh water

Areas of less-extensive aquifers having
smaller yields


Ground water sufficient for domestic and
livestock supplies can be found throughout
the country.

Larger ground-water supplies for industry,
municipal use, and irrigation are obtained
from high-permeability rocks and river
deposits (alluvium).


LII








Where Ground-Water

Use Is Concentrated


RELATIVE PRODUCTION OF GROUND WATER, 1980
In Millions of Gallons Per Day.
iFrom U.S. Water Resources Council, Bulletin 161


"G ~001 t


**oo


*000


01


* Although ground water is the main source of rural water supplies, and is the source
for many cities, those uses are relatively small compared to irrigation demand.
Irrigation accounted for about 70% of the ground-water production in 1980.
* Ground-water production for irrigation tripled between 1950 and 1980, increasing
from 20 to 60 billion gallons per day.
* Irrigation demand, and thus the largest ground-water production, is concentrated
in the semi-arid western states and in Florida.
* The four leading ground-water pumping states California, Texas, Nebraska,
and Idaho account for almost half the total national production of ground water.









Ground Water Serves

Many Users


Ground water provides 23% of the fresh water
used in the United States. In the 17 semi-arid western
states, it provides 38% of the fresh-water supply. It is
the chief supply for rural domestic and stock use, and
for small community supplies throughout the Nation.
Although not generally considered a "use," ground
water serves another vital function: it sustains stream
flows in dry weather. In highly permeable areas, ground
water is the main source of stream flow at all times.


All
Fresh
Water


Self-supplied
Industrial


Water Uses Supplied by Ground Water

35% of Public Supply Ground water is the most
efficient supply for medium-sized cities and small
communities because it does not require costly
reservoirs and aqueducts. Of the 100 largest
U.S. cities, 34 depend wholly or partly on ground
water. The largest populations (1980) served
entirely by ground water include Nassau-Suf-
folk Counties of Long Island, N.Y. (2.6 million),
Miami (1.6), San Antonio (1.1), Memphis (0.9),
Dayton (0.8), Honolulu (0.7), and Tucson (0.5).

80% of Rural Domestic and Stock Use Ground
water generally is the only feasible supply in most
of the Nation.

40% of Irrigation Ground water, where readily
available, is the most efficient supply because
it does not require storage and transport facilities.

6%o of Self-supplied Industrial Use Ground
water generally is unsuitable for very large indus-
trial supplies, such as power plant cooling, owing
to the huge concentrated demand at a single point.


KEY


Surface Water

Ground Water


Rural
Domestic
and Stock
S11 4.5


Fresh-Water Withdrawals in the United States, 1980, in billions of gallons per day.


LIII


Irrigation


Public
Supplies









Major Ground-Water Problems:


Overdraft

Overdraft, or ground-water "mining," is one of
the most serious problems we must face: it comes
about when withdrawals, either regionally or locally,
exceed the long-term average recharge, resulting in
continuing decline of water levels. In confined aquifers,
the decline generally is more rapid and severe than in
unconfined systems. Water levels may show sharp
declines locally without a regional overdraft, when
pumping exceeds the ability of the aquifer to transmit
water laterally to the area of the pumping depression.


Legal Contamination

Regional overdraft generally occurs in arid
areas of low recharge. Production from even a few
wells may be enough to exceed natural recharge.
Commonly, overdraft sets in before developers are
aware of the problem. Classic cases include the San
Joaquin Valley of California, the southern High Plains
of Texas, the Coastal Basin of southern California, and
the alluvial valleys of central Arizona.
In southern California, overdraft has induced land-
ward movement of sea water in the aquifers, and to
alleviate the problem, extensive fresh-water barriers -
rows of wells into which fresh water is injected have
been installed. In limestone terranes of the south-
eastern U.S., water-table declines have reactivated
subsidence in dormant sinkholes, sometimes with
catastrophic results.
The adverse effects of overdraft include increas-
ing energy costs for pumping as the water level de-
clines, added maintenance costs for lowering pumps
and deepening wells, land subsidence, and salt-water
intrusion in coastal sites or where inland salt waters
are nearby.


Local overdraft generally occurs at municipal
or industrial well fields where concentrated pumping
exceeds the ability of a confined aquifer to transmit
water laterally to the pumping center. Well-known
examples include Chicago, San Jose, and Savannah.
The adverse effects are similar to those of regional
overdraft, but are confined to a smaller area. With
reduction in pumpage, water levels recover rapidly.


I ~




-r


REGIONAL OVERDRAFT


Bench arkT88(5n/,. Bench mark G758 0
northwest of 33H1 1
+ 2
+ -f '4 WA-280 3

Hydrograp ,24 26- 33H drograph, 24, 26-34F1
(dept 977 feet)_ (depth 1,52 feet) 8
9
11
__'12
,- s !

- --------------------- --- I-I-I4I1I -- ---------------------_i i I 2


0t t 0


0 m 0
* U R-
0, Ct P


Water-level records from wells and sur-
face elevation changes at bench marks
near Delano, San Joaquin Valley, Califor-
nia, 1930-1970, show effects of prolonged
regional overdraft on pressure levels, and
land subsidence resulting from decreased
pressure in the confined aquifer. Imports
of surface water beginning in 1952 re-
versed pressure decline and halted subsi-
dence.


(From USGS Professional Paper 437-H)


Profile across southern High Plains of Texas AST
showing general ground-water conditions. The
Plains slope eastward and are cut off from river
recharge. Under natural conditions, spring dis-
charge was balanced by small infiltration from rainfall. Si gsr
Irrigation pumping now is about 100 times recharge, Springs
and water table is declining 1-5 feet per year. As water table 'ta P
approaches base of aquifer, pumping will necessarily cease. Bedrock

(From U.S. Water Resources Council Bulletin 16)



LOCAL OVERDRAFT



Profile through Honolulu, Hawaii showing effect 0 -SKM
of water table decline in permeable rocks open to ,so
the sea. Due to its lower density, fresh water floats p/
as a "lens" on sea water. Slight lowering of water \
levels by pumping in the fresh-water zone causes 1 / -' \
underlying sea water to rise toward wells. -
(Adapted from Todd and Meyer, 1971) -/ / "

1. .___ ..IA Ji /


0 2
Distance from Shoreline, km


Lines of equal decline of pressure surface at
Savannah, Georgia, 1933-54 (black lines) and
1955-75 (dashed blue lines), showing sharp de-
cline due to municipal pumping during the early
period, and a shift in decline toward the south-
west with reduction in municipal pumping.
Shaded area at center delineates moderate land
subsidence during early period.
(From Davis and others, 1977)


200
S 240
S280
5 320
9 360
S400
440
S480
S








Major Ground-Water Problems / continued


Legal


Ownership of ground water (a property right) and
its regulation have traditionally been a function of the
states. Currently, four basic doctrines of ground-water
ownership are applied in the U.S. In many states, exist-
ing law is inadequate to allocate the resource among
existing claimants, and takes no consideration of the
close relationship of surface and ground waters. In-
deed, some states apply different and incompatible
doctrines to surface and ground waters. Confusion
abounds as to what an individual's rights include.


The Four Doctrines of Ground-Water Rights

1. Riparian or Common-Law Doctrine -Holds
that an overlying land owner has absolute ownership
of underlying ground waters whenever he chooses
to exercise this right, with no limitation on amount of
use. Clearly, this principle cannot be equitably
applied in areas of water shortage.
2. Reasonable Use Doctrine An outgrowth of the
riparian doctrine. Restricts the right to ground
water to reasonable use. It implies that a land-
owner's right to use water can be limited when the
available supply is not sufficient to meet all demands.
3. Appropriation Doctrine -Recognizes the prin-
ciple of "first come, first served" in that the earliest
water users have the firmest right where supplies of
ground water are limited. In practice, the system
results in prohibition against new wells in areas
deemed to be fully developed.
4. Correlative Rights Doctrine -Holds that all
landowners have a proportionate right to ground
water needed to supply overlying lands. Where
overdevelopment exists, this leads to lengthy legal
adjudications to apportion the available supply.

Overriding Rights Even where water has been
fully allocated, certain "lurking" rights may apply
and be used to expropriate water from existing uses.
These include: (1) Federal reserved right to suffi-
cient water for the purpose of a land reservation;
(2) Indian reserved rights, similar to Federal re-
served rights, but applying to Indian reservations;
(3) Pueblo rights to communal water supplies in
former Spanish territories; and (4) the Federal
sovereign right to water for national security pur-
poses.

Main Problems Resulting from Legal Confusion

Insecurity as to future rights to water, which dis-
courages capital investment.
[ Inability to jointly manage surface and ground
waters in the most efficient combination.
Unrealistic limitations on economic growth in arid
areas.




- I.


GROUND-WATER LAWS


\A q

i I NEW MEN .E0O



Four different systems of owner-
ship apply to ground-water rights:

W RIPARIAN or COMMON LAW

I D REASONABLE USE

[ APPROPRIATION

CORRELATIVE RIGHTS
SW
2000
An illustration of legal complications
from the Central Valley, California,
where rights to surface water are
governed by the Appropriation Doc- E
trine, and rights to ground water by
the Correlative Rights Doctrine:
Overdraft from aquifers on the West
Side of SanJoaquin Valley has rever- .,
sed the regional ground-water flow
pattern. Ground water that formerly
discharged to the SanJoaquin River
system (1906 diagram, arrows) now
flows to the west, so the river now 2ooos
contributes to the ground water
(1966 diagram, green arrows). The 1
possibilities for litigation are end-
less, with any or all of hundreds of
holders of surface-water rights suing LEE
tens of thousands of ground-water
users.

(After USGS Professional Paper 437-E) 2:x -


A 1906
vs
1966









Major Ground-Water Problems / continued


Contamination / Principal


Contamination of ground water is a severe
problem because the contaminant generally travels
unobserved until detected in a water-supply well. Once
contaminated, an aquifer is difficult and expensive to
clean up. The contaminant disperses in the ground
water, is difficult to remove, and may persist for
decades. In almost all cases, prevention is simpler and
cheaper than cure.
Contaminants include an almost endless list of
inorganic chemicals, organic chemicals, biological
matter, radioactive compounds, and even physical
loads such as heat. The impacts on ground water may
range from aesthetic effects (such as unpleasant taste
or warm temperature) to imminent hazards to health.


Sources


Principal sources of pollution, in order of imp
tance nationally, include:
1. Industrial wastes
2. Municipal landfills
3. Agricultural chemicals
4. Septic system and cesspool effluents
5. Leaks from petroleum pipelines and storage ta
6. Animal wastes
7. Acid mine drainage
8. Oil-field brines
9. Salt-water intrusion
10. Irrigation return flow
The following four pages illustrate some of
major contamination sources.


r ~J








Major Ground-Water Problems / continued


9 INDUSTRIAL CONTAMINATION

Well Deep-Well
Disposal Injection Spills
Pond and

"/. *: .;. .Leaks




,". A ,llui
.-


Industrial wastes are disposed of in many ways
(From USGS Circular 875)


KEY: -- FRESH WATER CONTAMINATION CONTAMINATED GROUND WATER


A vast array of industrial chemicals, including large
volumes of liquid and solid toxic compounds, are
disposed of in seepage ponds and by shallow burial.
By 1981 the inventory of toxic wastes was 6 billion


cubic yards at 100,000 sites in the U. S. Radioactive
wastes are a special category of industrial wastes
owing to their high toxicity, but the amounts and
number of sites are small.


CONTAMINATION FROM UNDERGROUND STRUCTURES


Acid drainage, chiefly from thousands of abandoned
coal mines in the Appalachian Region, locally contamin-
ates ground water, which discharges to surface streams.
Acid mine drainage reportedly has severely degraded
11,000 miles of streams in the Appalachian area.


Underground coal mining is responsible for the disrup-
tion of overlying aquifers through the collapse of strata
above the coal, which drains the overlying materials
and aggravates acid-drainage problems, stemming from
oxidation of pyrite and other sulfur compounds.


BEFORE MINING AFTER MINING


-my









Major Ground-Water Problems / continued


MUNICIPAL CONTAMINATION


Precipitation on a landfill can leach chemicals
down into the ground-water reservoir,
potentially contaminating wells,
ponds, and streams.


In the humid areas of the country, rain and snow on a
landfill may carry dissolved substances downward,
delivering biologic, organic, and inorganic pollutants
to the ground water. The degree of hazard depends on
the geology of the site, design of the landfill, and char-
acter of the wastes.


SOLID WASTE-


----Clay a----d Silt
----- i -ay--an---


T

i I t,,'" 'I z ; "



Relatively Safe
Pollutants move slowly in clay and silt and many nox-
ious compounds are adsorbed on clay-mineral grains.


Most municipal trash is disposed of in such landfills.
Other important sources of municipal contamination
include sewage effluent, sludge disposal, and leaky
sewers.


.. WATER TABLE-

....^ ^ --^._ .......





Unsafe
Pollutants entrained directly in ground water.
(Illustrations from USGS Circular 601-F)




- F


Major Ground-Water Problems / continued


i AGRICULTURAL AND "NATURAL" CONTAMINATION


Plants consume water in the soil zone, but
remove little of the dissolved mineral matter,
invariably resulting in concentration of min-
erals in ground water. In addition, leaching of
fertilizers, pesticides, and soil amendments
occurs in all farming areas. In arid regions,
soluble minerals in the soil are dissolved by
irrigation water and carried to the water table,
further increasing the mineral content.


Ground water rising into the root zone
drowns plants and causes soil saliniza-
tion. Excessively shallow ground water
can cause extensive damage to plants,
soils, and structures. The remedy usually
lies in lowering the water table through
subsurface drains or pumping.


DOMESTIC CONTAMINATION
Some 40 million people in the U.S. are served by septic
systems or cesspools. Even with good design, mineral
contaminants reach the ground-water body. However,
in well-designed systems, particulate matter, organic,
bacteria, viruses, and many noxious constituents are


Production


filtered, adsorbed, or chemically altered before the
effluent reaches the water table. Barn yards and feed
lots also contribute animal wastes, which commonly
percolate to the ground-water body.


Pretreatment Disposal


Poorly designed water supply and sewage system recycles sewage effluent to well.









Major Ground-Water Problems / continued


CONTAMINATION FROM LIQUID WASTE

Prevention and Reclamation
WELLHEAD
PRESSURE
GAUGE
GAUGEWASTE FLUID FROM
INJECTION PUMP
CASING
PRESSURE -
GAUGE PREVENTION
MONITORING
WELL Toxic liquid wastes and other noxious
fluids may in some places be safely injected
LOOSE into deep permeable rocks far below fresh-
S 0SU CSOIL water aquifers. Such disposal generally is to
Deep saline (or otherwise unusable) ground
CONDUCTOR waters that are isolated from fresh-water
PIPE sources. Great care is required in well-casing
Design and operations to avoid leakage that
could endanger usable fresh-water supplies.
It is important in site selection to choose
CEMENT TO places where the hydraulic head of the injec-
SURFACE tion can be dissipated to avoid applying ex-
cess pressure to the well system or the receiv-
ing zone.
FRESH- Properly constructed oil wells are cased in
"--WATER
AQUIFER similar fashion, to safeguard ground waters,
.. but in many old oil-producing districts saline
SURFACE water escapes through leaky casings and
CASING holding ponds, causing extensive local con-
tamination.
CASING
SHOE



INJECTION .
CASING

LINED '
INJECTION-
TUBING SCAVENGER CONTROL
AND PUMP ASSEMBLY
OIL
PUMP PERFORATED RECOVERY
CLEAN CONTROLS WELL CASING TANK
WATER
OUTPUT

OIL QIA :0
,'...; .FILTER*
WTERBUOY .,-'
RECLAMATION

Contaminated zones can in some cases be
isolated using slurry trenches, grout curtains,
or sheet piling. Reclamation methods include
extraction of contaminated water for treat-
ment by means of interceptor wells and
trenches, or skimmer wells for light-weight
fluids. Some contaminants can be neutralized
in place with chemicals or biological agents.
Floating contaminants, such as oil from surface spills,
commonly can be removed with skimmer systems.








Information Required for

4 Ground-Water Problem Analysis and Decision-Making


Physical
framework











Hydrologic
stresses












Model
calibration


Prediction and
optimization
analysis


* Hydrogeologic maps showing extent and boundaries of all aquifers
and non-water-bearing rocks.
Topographic map showing surface-water bodies and land forms.
Water-table, bedrock-configuration, and saturated-thickness maps.
B Transmissivity maps showing aquifers and boundaries.
Map showing variations in storage coefficient.
B Relation of saturated thickness to transmissivity.
Hydraulic connection of streams to aquifers.



B Type and extent of recharge areas (irrigated areas, recharge basins,
recharge wells, natural recharge areas).
* Surface-water diversions.
B Ground-water pumpage (distribution in time and space).
* Precipitation.
B Areal distribution of water quality in aquifer.
* Streamflow quality (distribution in time and space).
B Geochemical and hydraulic relations of rocks, natural water, and
artificially introduced water or waste liquids.


Water-level change maps and hydrographs.
Streamflow, including gain and loss measurements.
History of pumping rates and distribution of pumpage.



Economic information on water supply and demand.
Legal and administrative rules.
Environmental factors.
Other social considerations.


MI




- -


Information Required for

, Ground-Water Problem Analysis and Decision-Making


Physical
framework











Hydrologic
stresses











Model
calibration


Prediction and
optimization
analysis


" Hydrogeologic maps showing extent and boundaries of all aquifers
and non-water-bearing rocks.
" Topographic map showing surface-water bodies and land forms.
" Water-table, bedrock-configuration, and saturated-thickness maps.
* Transmissivity maps showing aquifers and boundaries.
" Map showing variations in storage coefficient.
B Relation of saturated thickness to transmissivity.
" Hydraulic connection of streams to aquifers.



" Type and extent of recharge areas (irrigated areas, recharge basins,
recharge wells, natural recharge areas).
" Surface-water diversions.
" Ground-water pumpage (distribution in time and space).
" Precipitation.
* Areal distribution of water quality in aquifer.
" Streamflow quality (distribution in time and space).
" Geochemical and hydraulic relations of rocks, natural water, and
artificially introduced water or waste liquids.


Water-level change maps and hydrographs.
Streamflow, including gain and loss measurements.
History of pumping rates and distribution of pumpage.



Economic information on water supply and demand.
Legal and administrative rules.
Environmental factors.
Other social considerations.











0G3und-Water Issues


3. Ground-Water Quality -AIPG believes that the
present patchwork of Federal and State law aimed
at protecting ground water is of limited effective-
ness, if not counterproductive. Indeed, Federal
pressure for cleanup of surface waters has placed
more stress on land disposal of pollutants, resulting
in increased contamination of ground waters.
a. AIPG supports the concept of explicitly recog-
nizing society's need to dispose of wastes, and
favors adoption of a policy permitting limited de-
gradation of surface and ground waters in keep-
ing with economic reality. With respect to
ground waters, AIPG believes the National
policy should focus on prevention of significant
impairment of socially and economically im-
portant ground-water supplies.
b. AIPG supports the concept that National policy
should have the objective of protecting specific
existing high-value water uses. Standards for re-
ceiving surface and ground waters should be suf-
ficient to protect existing uses, and uses in the
Reasonably foreseeable future, taking into
account the cost of achieving them.
c. AIPG urges continuation of the system of stand-
ards implemented through a national waste-dis-
charge permit system, administered by the
states under Federal guidelines. AIPG supports
the concept that Federal agencies should inter-
vene in local enforcement matters only upon a
judicial finding that a state is not enforcing Fed-
eral law.
d. AIPG believes that Federal standard-setting
should be confined to protection of public health.
e. AIPG supports the principle of use of perform-
ance standards rather than prescriptive rules,
enforced through a system of permits for major-
polluting facilities, requiring competent profes-
sional design, operation, and monitoring.
f. AIPG believes consideration should be given to
implementing ground-water quality laws through
a system of economic incentives for compliance,
including taxing of waste discharges.


4. Underground Operations Oil production,
deep-well waste disposal, mine openings, and other
facilities below the water table all pose potential
danger to the physical integrity of aquifers and to
ground-water quality on a local scale.
a. AIPG supports the concept that states should
regulate drilling and other forms of deep con-
struction through a system of permits and licen-
sing of qualified operators. Permits should
cover construction, operation, and proper
abandonment of major facilities where they pose
significant hazards to aquifers.
b. AIPG supports Federal financial assistance to
states, interstate organizations, trade associa-
tions, and professional societies to develop ap-
propriate model codes for underground
operations.

5. Data and Research -AIPG believes that, as the
magnitude and complexity of ground-water prob-
lems continues to grow, there is need for continued
support of data and research programs that provide
the basis for rational decision-making. AIPG is con-
cerned that funding of these programs in recent
years has not kept pace with economic growth, or
the increasing complexity of ground-water prob-
lems. AIPG supports the concept of matching fund-
ing of ground-water data and research programs by
Federal and State governments, as exemplified by
the time-tested state-Federal cooperative water-re-
sources programs of the U.S. Geological Survey.
AIPG urges Congress to appropriate sufficient
funds for programs calling for equal financial contri-
butions by state and Federal governments to assure
that state offerings will be fully met.













Glossary


Hydrology, like other branches of science, has its
own terminology, and an understanding of certain
terms is essential. The definitions here (adapted from
Hobba, 1981) have been simplified and shortened as
much as possible.

Alluvium Debris from erosion, consisting of some
mixture of clay particles, sand, pebbles, or larger
rocks. Usually a good, porous storage medium
for ground water.

Aquifer Rock formation that contains sufficient
saturated permeable material to yield significant
amounts of water to wells or springs.

Aquifer, confined (or artesian) The water level in
a well tapping a confined aquifer will rise above the
top of the aquifer because of hydrostatic pressure.

Aquifer, unconfined The water level in a well tap-
ping an unconfined aquifer will not rise above the
water table.

Capillary force A form of water surface tension,
causing water to move through tiny pores in rock
or soil due to molecular attraction between the
water and earth materials.

Capillary water Water held in tiny openings in
rock or soil by capillary force.

Depression, cone of The depression in the water
table or other potentiometric surface caused by
the withdrawal of water from a well.

Drawdown in a wed The vertical drop of the
water level in a well caused by pumping.

Evapotranspiration Evaporation from water
surfaces, plus transpiration from plants.

Fault A fracture in the Earth's crust accompanied
by displacement of one side of the fracture with
respect to the other.

Fracture A break in rock that may be caused by
compressional or tensional forces.

Gradient, hydraulic The change of pressure
head per unit distance from one point to another
in an aquifer.


Ground water Water contained in the zone o
saturation in the rock. (See surface water.)

Head Pressure, expressed as the height of;
column of water that can be supported by th
pressure.

Hydraulic conductivity A medium has a hydrate
lic conductivity of unit length per unit time, if it wi
transmit in unit time a unit volume of water at th
prevailing viscosity through a cross section of un
area, measured at right angles to the direction (
flow, under a hydraulic gradient of unit change i:
head through unit length of flow.

Permeability, intrinsic A measure of the relatih
ease with which a porous medium can transmit
liquid under a potential gradient.

pH A measure of the relative acidity of water
Below 7 is increasingly acid, 7.0 is neutral, a,
above 7 is increasingly alkaline (basic).

Porosity, primary Interstices that were create
at the time the rocks were formed.

Potentiometric surface An imaginary surfa
that everywhere coincides with the static level
water in a confined aquifer.

Precipitation, atmospheric Water in the fo
of hail, mist, rain, sleet, or snow that falls to I
Earth's surface.

Recovery of pumped well When pumping fror
well ceases, the water level rises (or recove
to approximately the level (static level) bef.
pumping.

Surface water Water on the surface of the Eai
including snow and ice. (See ground water.)

Transmissivity The rate at which water of a r
vailing viscosity is transmitted through a unit wi
of aquifer under a unit hydraulic gradient.

Water table That surface in an unconfined w.
body at which pressure is atmospheric; gene
the top of the saturated zone.
Zone of saturation Rock or soil in which e%
available space is filled with water.


r ~7.











0G3und-Water Issues


3. Ground-Water Quality -AIPG believes that the
present patchwork of Federal and State law aimed
at protecting ground water is of limited effective-
ness, if not counterproductive. Indeed, Federal
pressure for cleanup of surface waters has placed
more stress on land disposal of pollutants, resulting
in increased contamination of ground waters.
a. AIPG supports the concept of explicitly recog-
nizing society's need to dispose of wastes, and
favors adoption of a policy permitting limited de-
gradation of surface and ground waters in keep-
ing with economic reality. With respect to
ground waters, AIPG believes the National
policy should focus on prevention of significant
impairment of socially and economically im-
portant ground-water supplies.
b. AIPG supports the concept that National policy
should have the objective of protecting specific
existing high-value water uses. Standards for re-
ceiving surface and ground waters should be suf-
ficient to protect existing uses, and uses in the
Reasonably foreseeable future, taking into
account the cost of achieving them.
c. AIPG urges continuation of the system of stand-
ards implemented through a national waste-dis-
charge permit system, administered by the
states under Federal guidelines. AIPG supports
the concept that Federal agencies should inter-
vene in local enforcement matters only upon a
judicial finding that a state is not enforcing Fed-
eral law.
d. AIPG believes that Federal standard-setting
should be confined to protection of public health.
e. AIPG supports the principle of use of perform-
ance standards rather than prescriptive rules,
enforced through a system of permits for major-
polluting facilities, requiring competent profes-
sional design, operation, and monitoring.
f. AIPG believes consideration should be given to
implementing ground-water quality laws through
a system of economic incentives for compliance,
including taxing of waste discharges.


4. Underground Operations Oil production,
deep-well waste disposal, mine openings, and other
facilities below the water table all pose potential
danger to the physical integrity of aquifers and to
ground-water quality on a local scale.
a. AIPG supports the concept that states should
regulate drilling and other forms of deep con-
struction through a system of permits and licen-
sing of qualified operators. Permits should
cover construction, operation, and proper
abandonment of major facilities where they pose
significant hazards to aquifers.
b. AIPG supports Federal financial assistance to
states, interstate organizations, trade associa-
tions, and professional societies to develop ap-
propriate model codes for underground
operations.

5. Data and Research -AIPG believes that, as the
magnitude and complexity of ground-water prob-
lems continues to grow, there is need for continued
support of data and research programs that provide
the basis for rational decision-making. AIPG is con-
cerned that funding of these programs in recent
years has not kept pace with economic growth, or
the increasing complexity of ground-water prob-
lems. AIPG supports the concept of matching fund-
ing of ground-water data and research programs by
Federal and State governments, as exemplified by
the time-tested state-Federal cooperative water-re-
sources programs of the U.S. Geological Survey.
AIPG urges Congress to appropriate sufficient
funds for programs calling for equal financial contri-
butions by state and Federal governments to assure
that state offerings will be fully met.




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