?,EPA
United States
Kvironmental Protection
Agency
Region 8
EPA908-R4)3-001
November 2003
GROUND WATER IN
REGION 8 STATES
A Report on the Status of
Ground-Water
Management and Protection
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Water Cycle illustration
Stephen Adduci, Adduci Studios
Purdue Pesticide Programs, Purdue University
O
Printed on Recycled Paper
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GROUND WATER IN EPA REGION 8 STATES
A Report on the Status of Ground-Water Resources,
Management and Protection
by Darcy Campbell, Marcella Hutchinson,
Richard Muza, and Mike AVireman,
Ground Water/Source Water Team, U.S. EPA Region 8
Denver, Colorado
2003
Special thanks to: Beth Hall (USEPA), George Ritz (USGS), Karen Hamilton (USEPA),
John Moore, and Paul Osborae (USEPA).
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TABLE OF CONTENTS
I. INTRODUCTION 1
I.A. Why Care About Ground Water? ! 1
Ground-Water Contamination 3
Ground-Water Protection 5
I.B. Basic Hydrogeology 5
I.C. Ground-Water Classification 11
I.D. Ground-Water Sensitivity and Vulnerability 13
II. GROUND-WATER OCCURRENCE AND USE IN EPA REGION 8 15
II.A. Major Aquifers and Aquifer Systems 15
II.B. Ground-Water Use ' 28
Agricultural Use 28
Public Water Supply and Private Domestic Water Supply Use 31
Public Water Supply 31
Private Domestic Water Supply 34
Ground-Water "Mining" 34
III. GROUND-WATER QUALITY IN REGION 8 37
III.A. Natural Ground-Water Quality 37
III.B. Contamination and Threats to Ground Water 38
Sources of Ground-Water Contamination 38
Agriculture 42
Mining 45
Underground Storage Tanks 46
Waste Disposal 46
Oil and Gas Production 50
Hazardous Waste Sites 50
Urban and Suburban Sources 51
III.C. Ground-Water Quality Monitoring and Data: Strengths
And Limitations 53
Introduction 53
The USGS National Water Quality Assessment
(NAWQA) Program 53
State Ground-Water Quality Monitoring 54
Compliance Monitoring 56
Drinking Water Monitoring 56
Data and Information 57
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TABLE OF CONTENTS (cont.)
IV. GROUND-WATER PROTECTION AND MANAGEMENT PROGRAMS 59
IV.A. EPA Ground-Water Protection Programs and Authorities 59
IV.B, State Ground-Water Protection Programs 69
Ground-Water Classification 69
Application of Water-Quality Standards to Ground Water 72
Ground-Water Discharge Permits 73
State Management Initiatives 74
IV.C. Tribal Ground-Water Protection Programs 78
IV.D. City/County and Other Success Stories 80
V. MEETING THE CHALLENGES OF GROUND-WATER MANAGEMENT IN
REGION 8 ' 84
REFERENCES
APPENDIX A,
APPENDIX B.
APPENDIX C.
GROUND-WATER GLOSSARY
STATE AND EPA GROUND-WATER PROGRAM WEBSITES
USGS NAWQA SUMMARY
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LIST OF FIGURES
Figure 1. Use of Ground Water for Drinking Water 2
Figure 2. Fresh Ground-Water Withdrawals by Water-Use Category in Region 8 4
Figure 3. Aquifers and Confining Beds 6
Figure 4. Ground-Water Recharge and Discharge Zones , 8
Figure 5. Interaction of Streams and Ground Water 10
Figure 6. Ground-Water Regions of the U.S 12
Figure 7. Map of Major Aquifers in Colorado 17
Figure 8. Map of Major Aquifers in Montana 19
Figure 9. Map of Major Aquifers in North Dakota 21
Figure 10. Map of Major Aquifers in South Dakota 23
Figure 11. Map of Major Aquifers in Utah 25
Figure 12. Map of Major Aquifers in Wyoming 27
Figure 13. Irrigated Agricultural Use of Ground Water in Region 8 by Year 30
Figure 14. Region 8 Ground-Water-Based Public Water Supplies by State 32
Figure 15. Public Water Supply Use in Region 8 by Year 33
Figure 16. Rural Domestic Ground Water Use 35
Figure 17. Nitrate in Ground Water 43
Figure 18. Underground Storage Tank with Monitoring Wells 47
Figure 19. Septic Tank Schematic 49
Figure 20. Fertilizer, Herbicide and Pesticide Use on Lawns Can Contaminate Ground Water . 52
LIST OF TABLES
Table 1. Major Aquifers/Aquifer Systems in Colorado 16
Table 2. Major Aquifers/Aquifer Systems in Montana 18
Table 3, Major Aquifers/Aquifer Systems in North Dakota 20
Table 4. Major Aquifers/Aquifer Systems in South Dakota 22
Table 5. Major Aquifers/Aquifer Systems in Utah 24
Table 6. Major Aquifers/Aquifer Systems in Wyoming 26
Table 7. Fresh Ground-Water Withdrawals by Water-Use Category and State, 1995 29
Table 8. Sources of Ground-Water Contamination by State 40
Table 9. Office of Underground Storage Tanks, FY02 Semi-Annual Activities 48
Table 10. EPA Programs and Authorities to Protect and Remediate Ground Water 60
Table 11. Overview of State Ground-Water Protection Program Elements 71
in
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GROUND WATER IN EPA REGION 8 STATES
A Report on the Status of Ground-Water Resources, Management and
Protection
EXECUTIVE SUMMARY
Introduction
Ground water is a critical resource in EPA Region 8, which includes the states of Colorado, Utah,
Wyoming, North Dakota, South Dakota and Montana. Ground water is an important source of
water for public water supply, agricultural, industrial, and household uses in each of these states.
It also serves as a significant source of recharge water for lakes, streams, and wetlands (EPA,
1999).
The purpose of this document is to provide a general overview of the nature and status of
ground-water resources within EPA Region 8, including:
• ground-water occurrence and use;
• a description of some common threats to ground-water resources;
a summary of what EPA and its partners are doing to protect ground water; and
• findings and recommendations compiled by EPA Region 8 staff.
Ground-Water Occurrence and Use
Within the Region 8 states, ground water occurs in two types of geologic formations;
unconsolidated surficial deposits and semi-consolidated to consolidated bedrock formations.
Unconsolidated deposits include clay, silt, sand and gravel that was deposited in river valleys and
intermontane basins. Where these deposits are thick and permeable, they comprise high-yielding
aquifers. Ground water that occurs in these types of aquifers is typically directly connected to
streams and rivers. Unconsolidated, surficial deposits were the first aquifers to be developed
because they were readily accessible and yielded relatively large quantities of water to wells.
However, they are also sensitive to contamination from land-use activities. Recharge to these
types of aquifers is primarily via infiltration of rain and snow across the areal extent of the aquifer.
Ground water also occurs in the sedimentary bedrock formations (sandstone, siltstone, limestone)
that underlie many of the large structural basins that occur throughout the Region 8 states. These
bedrock formations comprise aquifers that store large volumes of water but do not yield water to
wells as readily as the unconsolidated deposits. Many sedimentary bedrock aquifers will yield
only moderate amounts of water, though some sandstone and limestone formations will yield
enough water to supply municipal and irrigation wells. Recharge to these types of aquifers is
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more limited than recharge to surficial unconsolidated aquifers. Ground water also occurs within
the fractured igneous and metamorphic rocks that comprise the Rocky Mountains. These aquifers
are typically low-yielding and often will not provide significant amounts of water to wells. This is
because water only occurs and moves within the fractures within the rock.
The major aquifers and aquifer systems within the Region 8 states have been mapped in detail by
the USGS and State Geological Surveys. However the water quality, recharge and discharge
areas and flow systems within these aquifers are not as well characterized.
Ground-water use within the Region 8 states is significant. In 1995, more than 3.8 billion gallons
of ground water were withdrawn every day for human use. Irrigation and livestock watering
accounted for 75% of this use, while domestic and public drinking water accounted for 17% of
the total use. From 75% to 90% of public water systems in each state in Region 8 depended on
ground water to serve their customers in the year 2000. More than 2.6 million people in Region 8
relied solely on ground water supplied by community water systems in 2000. Another 2.2 million
people in Region 8 got their water from community water systems that use both ground water and
surface water, in the year 2000. As the population increases in the West, especially in the
mountainous areas, ground water use is increasing dramatically for domestic use.
Key Conclusions and Recommendations
Ground-Water Management Should Be Aquifer-Based. Aquifers are the natural units of
management for ground water just as a stream, lake or watershed is a natural unit of management
for surface water. Ground-water management often proceeds without all parties recognizing that
they are managing the same aquifer. This has resulted in a fragmented, often ineffective, and
sometimes contradictory, non-resource-based approach to ground-water management. Effective
ground-water protection and management relies on recognition by state and local governments
that surface water and ground water are hydraulically connected. Watershed management has
typically ignored the connection between ground water and surface water, even though ground
water can be a critical factor with regard to both the quantity and quality of streams and lakes.
Integration of ground-water management and surface-water management at the state and local
level is critical.
Monitoring Should Be A Key Element Of Ground-Water Management. There are
insufficient data to truly determine the status of ground-water quality for most major aquifers and
aquifer systems in Region 8. While there are many monitoring efforts conducted by numerous
agencies, there is little consistency in monitoring programs, data are not shared effectively among
the programs, various entities are often not aware of monitoring by others, many of the data are
not entered on computer databases, and many databases are not compatible. Also, the amount of
monitoring being done is very limited relative to the size of the resource. The result is a
patchwork of data useful for informed management decisions on a localized, site-specific level,
but of less value for making state or region-wide conclusions about status and trends. An up-to-
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date assessment of the existing data is needed in each Region 8 state to identify data needs so that
a more comprehensive, coordinated ground-water monitoring network can be developed to focus
on monitoring high priority aquifers or regions.
Prevention of Contamination Is More Effective Than Cleanup. Because cleaning up aquifers
after they are contaminated is difficult and expensive, preventing contamination is much more
sensible than trying to clean it up. However, federal and state governments spend hundreds of
millions of dollars per year on ground-water remediation, and only a few million dollars per year
on prevention of contamination. Nationally, the average capital costs for ground-water
remediation systems range from a low of approximately $500,000 for passive systems to a high of
about $3,500,000 for pump and treat systems (USEPA 1999b and USEPA 2001). Annual
operating costs for such systems add an average cost of approximately $70,000 to $700,000 per
year. Significantly more money should be allocated to prevention efforts, including:
• public education regarding how contamination occurs;
• assessments of sensitivity and vulnerability of aquifers and ground water;
• well head protection/source water assessment and protection;
• management of recharge areas; and
• ambient monitoring to determine water quality trends.
Non-Point Source Contamination Of Ground Water Is Still A Significant Problem. Federal,
state and local governments have made insufficient progress in establishing effective programs
aimed at reducing non-point source contamination. The most common non-point source
contaminants include agricultural chemicals, sediment and urban runoff.
Effective Ground-Water Management Requires Adequate Funding. Currently, ground-
water characterization, monitoring and management is inadequately funded throughout most of
the country, including EPA Region 8. As ground-water development and use increases in Region
8 and elsewhere it will be necessary to strengthen the commitment to sustainable development of
ground-water resources. In the future, federal, state and local governments will face serious
issues related to providing a safe, sustainable water supply to satisfy beneficial uses. Tough
decisions will be required related to choosing between: protection versus remediation of ground
water, and mining of ground-water resources vs. sustainable development. To prepare for these
management issues it is vital to provide adequate funding for ground-water/aquifer
characterization, monitoring and conjunctive management of ground water and surface water.
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Current Issues in Ground-Water Management
The following are current areas of research related to ground water:
• microorganisms in ground water;
• organic wastewater contaminants such as Pharmaceuticals, fragrances, dyes, antibiotics,
caffeine, and hormones;
• fractured rock aquifers;
- fuel oxygenates such as MTBE; and
• perchlorate
Vll
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GROUND WATER IN EPA REGION 8 STATES
L INTRODUCTION
Ground water is an important resource in EPA Region 8 states (Figure 1), which include
Colorado, Utah, Wyoming, North Dakota, South Dakota and Montana. Ground water is a
significant source of water for public water supply, agricultural, industrial, and private domestic
(household) uses in each of these states. It is a critical source of water for lakes, streams, and
wetlands (U.S. EPA, 1999a). Please note that italicized words are defined in the glossary
(Appendix A).
The purpose of this report is to describe the nature and status of ground-water resources in EPA
Region 8. It is written for water managers at the city, county, state and federal level, and for the
interested public. It includes:
* An introduction to ground-water occurrence and use;
• A description of some common threats to ground-water resources;
• A summary of what EPA and its partners are doing to protect ground water; and
• Findings and recommendations.
LA. WHY CARE ABOUT GROUND WATER?
Ground water is an essential natural resource. It is water
found beneath the Earth's surface, which supplies wells and
springs.
Ground water also contributes to flow in many streams and
rivers, and helps maintain lake levels. It strongly influences
river and wetland habitats for fauna and flora. The U.S.
Geological Survey estimated that the ground-water
contribution to all streamflow in the Nation may be as large
as 50% (Winter and others, 1999).
The United States relies heavily on ground water to meet its
water needs. Ground water accounts for about 25 percent of
all fresh water used in the Nation today. Ground water
provides about 40 percent of the Nation's public water
supply. It is the source of private domestic (household) water
In the continental
U.S. about 86.5% of
our fresh water is
beneath the ground,
13.4% is in lakes,
0.13% is in the
atmosphere, 0.05% is
glacier ice, and only
0.03% is in streams
and rivers! (GWMR
2001). Fresh water is
low in salts and is
usable for most
purposes, as opposed
to sea water.
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EXPLANATION
60 Estimated percentage of
population in a State
using ground water aa
R-\ drinking water in 1995
Figure 1. Use of Ground Water for Drinking Water (after Solley and others, 1998)
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for more than 40 million people, including most of the nation's rural population. It is a
significant source of drinking water in every state in the Nation (Figure 1). Ground water is also
the Nation's principal reserve of fresh water and represents much of the potential future water
supply.
Within Region 8, 78% of the Public Water Systems rely on ground water (U.S. EPA, 2001).
Drinking water from ground-water sources is served to about 2.5 million people in Region 8,
through nearly 6,000 public water systems. Approximately 1 million rural residents within
Region 8 rely on ground water from springs and wells for their private domestic (household)
needs (Solley and others, 1998). Since much of the surface water in the semi-arid to arid
climates of Region 8 is already appropriated for use, many areas are relying on ground water to
meet the needs of growing populations. Colorado's Denver metropolitan area and Utah's Salt
Lake City area are two well-known examples where ground water is being used to meet the
demands of rapidly growing urban populations. Ground water is also the source of much of the
water used for irrigation in Region 8, supporting millions of dollars worth of food production
(Figure 2).
In 1991, Russell
and others
estimated that
up to a trillion
dollars will be
spent in the
following 30
years on
cleanup of
contaminated
soil and ground
water across the
Nation. (Russell
and others,
1991)
Ground-Water Contamination
A recent study by the Worldwatch Institute (Sampat, 2000) reported
that toxic chemicals from man-made sources are contaminating
ground water on every inhabited continent. This first global survey
of ground-water pollution shows that pesticides, nitrogen fertilizers,
industrial chemicals, and heavy metals are contaminating ground
water. The damage is often worst in the very places where people
most need the resource. Since ground water moves slowly through
an aquifer, it is commonly difficult to flush out or dilute toxic
chemicals. Cleanup efforts are expensive and sometimes
unsuccessful.
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Figure 2. Fresh Ground-Water Withdrawals
by Water-Use Category in Region 8
% Use
2.1%
0.7%
14.7%
73.0%
Irrigation
Public Water Supply
Industrial-Commercial
Mining
Livestock
Domestic
Thermoelectric
Source: Solley and others, 1998
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Ground-Water Protection
In 1999, EPA released the "Safe Drinking Water Act, Section 1429 Ground Water Report to
Congress" (EPA, 1999a). EPA reviewed the status and effectiveness of state ground-water
protection programs and examined our Nation's approach to protecting ground water. The
findings of this report include:
• From what we know at most locations around the Nation, ground water is generally of
good quality but can be threatened by point and nonpoint sources of contamination, as
well as depletion by overpumping.
• State water-quality agencies have made considerable progress in implementing federal
and state programs aimed at specific contamination concerns.
• Most state agencies responsible for ground-water protection agree that a comprehensive,
resource-based approach is best to protect ground water.
• States have identified three primary barriers to achieving a more comprehensive
approach:
1) A fragmentation of ground-water programs among many different state
agencies with conflicting priorities and goals, which impedes effective
management;
2) A lack of scientific understanding of ground-water resources both locally
and regionally (e.g., the physical nature of the aquifers, behavior of
contaminants, interaction of ground water and surface water, etc.); and
3) A lack of funding targeted directly to protecting ground-water resources.
Ground water protection is often not a high priority for funding. Mandated
programs usually prevail for funding.
The EPA report concluded that the critical management question is how to increase efforts to
prevent new ground-water contamination while concurrently cleaning up contaminated ground
water.
I.B. BASIC HYDROGEOLOGY
Ground water is present in aquifers, geologic units that are capable of storing and transmiting
usable quantities of water to wells or springs (see glossary, Appendix A). The ground water
present in aquifers occurs under either -water table (unconfined) or artesian (confined) conditions
(Figure 3). Unconfined aquifers have no geologic beds such as clay above them that prevent a
ground water connection to the atmosphere. In an unconfined aquifer, the depth to the water
table varies from at or near the land surface to hundreds of feet below the land surface. On a
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regional scale the configuration of the water table is commonly a subdued replica of the land-
surface topography. Confined aquifers are overlain by geologic material that does not transmit
water readily, such as clay. This results in the water in the aquifer being under pressure that is
significantly greater than atmospheric pressure.
Ground water interacts with surface water through recharge and discharge zones (Figure 4).
Ground-water recharge occurs where precipitation or surface water infiltrates soil under sufficient
hydraulic head to reach saturated zones. Ground-water discharge occurs as evapotranspiration
to the atmosphere, or as ground-water flow into streams, springs, lakes, or wetlands. Hydraulic
gradient, hydraulic conductivity, andporosity govern the movement of ground water from
recharge to discharge zones. Discharge to surface water can occur from alluvial deposits into
streams, from glacial deposits into lakes, and from aquifers into wetlands. Aquifers may also be
hydraulically connected to each other. Major discharge from bedrock aquifers may also occur via
large springs.
The area! extent of ground-water flow systems (which may
include several aquifers) varies from a few square miles or less to
tens of thousands of square miles. The age of ground water
increases steadily along a particular flow path from an area of
recharge to an area of discharge (Figure 4). In most aquifers,
the velocities of ground-water flow generally are low (e.g., feet
per year) compared to the velocities of streamflow (e.g., feet per
second).
The relatively slow movement of ground water through the
subsurface allows long contact of the water with the minerals
that make up the geologic units of an aquifer. These minerals
will dissolve to a greater or lesser degree so that ground water
increases in mineral content along the flow path. Wide
variations occur in the chemical character of ground water, even
within small regions, due to the many variables in chemical
processes of the subsurface. The dissolved minerals in ground
water will affect its usefulness for various purposes. However,
most ground water contains no suspended matter and fewer bacteria than surface water, making
untreated ground water superior in sanitary quality to untreated surface water in many cases
(Driscoll 1986).
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RECHARGE AREA
DISCHARGE AREA
g
Figure 4. Ground-Water Recharge and Discharge Zones
(Winter and others, 1999)
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Ground-Water/Surface-Water Interaction
Recently, scientists have become more knowledgeable about the complex interaction that exists
between ground and surface water (Figure 5 and Winter and others, 1999). Recent research
attention has been focused on the hyporheic zone, the subsurface zone beneath a stream or lake
where ground water and surface water are in constant interaction. The chemical, biological and
hydraulic processes that occur in this zone are very important for maintaining suitable water
quality and ecological conditions in overlying surface waters.
Since much ground-water contamination occurs in shallow aquifers that are directly connected to
surface water, ground water can be a major and potentially long-term contributor to surface-water
contamination.
Understanding this link between ground water and surface water is important for managing both
water quantity and quality. Ground water supplies significant amounts of baseflow to streams
and rivers for most of the year, and provides inflow to wetlands. Ground-water withdrawals are
reducing stream flows in some areas. In 1996, the Montana Department of Natural Resources
prohibited ground water withdrawals from 5 basins in order to protect instream flows. Ground
water withdrawals from the Arkansas River valley-fill aquifer in Colorado has affected
streamflow to such an extent that Kansas sued Colorado for violating the Arkansas River
Compact. The U.S. Supreme Court agreed with Kansas.
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GAINING STREAM
Flow direction
LOSING STREAM
Flow direction
LOSING STREAM THAT IS DISCONNECTED
FROM THE WATER TABLE
Flow direction
Figure 5. Interaction of Streams and Ground Water
(Winter and others, 1999)
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I.C. GROUND-WATER CLASSIFICATION
Like the classification framework for surface water that employs a hierarchy of units for resource
characterization and management purposes (i.e., watersheds, basins, hydrologic units, etc.), a
similar framework for ground water can be useful for understanding, classifying and mapping
ground-water resources. The hierarchical classification presented here is based on mappable
features that control ground water occurrence, flow and quality. In order of descending scale, the
classification units are ground-water regions, hydrogeologic settings, aquifers, aquifer zones, and
aquifer sites.
Heath (1984) built on the work of Meinzer (1923) and Thomas (1952) to map 15 ground-water
regions in the United States, as shown in Figure 6.
GROUND-WATER CLASSIFICATION SUMMARY
UNIT
DEFINITION
Ground-Water Region
Geographic areas in which the composition,
arrangement, and structure of rock units that
affect the occurrence and availability of
ground water are similar. See Figure 6
(Heath, 1984).
Hydrogeologic Settings
An association of hydrostratigraphic units as
defined by mappable hydrogeologic features;
these units delineate the typical geologic and
hydrologic configurations that are found in
each Ground-Water Region.
Aquifers
A water-bearing geologic formation, group of
formations, or part of a formation that yields
usable quantities of water to a well or spring.
Aquifer Zones
Subdivisions of aquifers with differing
hydrologic conditions; includes recharge and
discharge areas as well as unconfmed and
confined areas.
Aquifer Sites
Springs and sinks may be single points,
clusters of points, or linear features along
streams.
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2, Alluvial Basin
500 MILES
-y:
800 KILOMETERS
7. Glaciated
Central
region
6. Mongtactated
Central
region
Figure 6. Ground-Water Regions of the U.S. (Heath, 1984)
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LD. GROUND -WATER SENSITIVITY AND VULNERABILITY
The concepts of ground-water sensitivity and vulnerability are a response to the increasing public
concern regarding ground-water contamination, and the need to protect clean ground water from
future contamination. A number of methods have been developed to assess the sensitivity and
vulnerability of ground water or aquifers. Furthermore, scientists have developed ways to
determine vulnerability of ground water or aquifers to water quality degradation by specific
contaminants or groups of contaminants. In 1996, the American Society of Testing and Materials
(ASTM) published a Standard Guide for Selection of Methods for Assessing Ground Water or
Aquifer Sensitivity and Vulnerability (ASTM, 1996).
Ground-water or aquifer sensitivity is the potential for ground water or an aquifer to become
contaminated based on intrinsic hvdrogeologic
characteristics. Sensitivity is not dependant on land-use
practices or contaminant characteristics. Instead, it is
primarily controlled by the hydrogeologic properties and
processes on the surface and in the subsurface.
Hydrogeologic properties that significantly affect ground-
water or aquifer sensitivity include: soil properties, vadose
zone characteristics, depth to ground water, recharge,
aquifer geology and hydrology.
Ground-water
sensitivity: the potential
for ground water to
become contaminated
based on hydrogeologic
characteristics such as soil
properties, depth to
ground water, recharge,
etc.
Ground-water
vulnerability: the relative
ease with which a
contaminant can migrate
to ground water under a
given set hydrogeologic
and land use conditions.
Ground-water or aquifer vulnerability is the relative
ease with which a contaminant can migrate to ground
water or an aquifer under a given set of land use practices.
contaminant characteristics, and sensitivity conditions.
Vulnerability assessments determine the potential impact
to ground water or an aquifer from specific land uses or
contaminants.
Sensitivity and vulnerability assessment methods can be
applied to a variety of hydrogeologic settings, whether or
not they contain specifically identified and mapped
aquifers. The methods developed to date are most applicable to hydrogeologic settings or
aquifers where intergranular ground-water flow is dominant. These include unconsolidated
geologic deposits such as alluvium and terrace deposits, valley-fill aquifers, glacial outwash and
consolidated rocks such as sandstone and siltstone. There are very few methods developed for
hydrogeologic settings dominated by flow in fractured rocks or flow in solution openings. This
is primarily because it is difficult to obtain field data that describe flow in fractured rock settings.
Most methods provide a relative ranking or assessment of sensitivity or vulnerability. It is
important to note that a low sensitivity or vulnerability does not mean that ground water or an
aquifer cannot become contaminated, nor does a high sensitivity or vulnerability mean that an
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aquifer is contaminated. Ground-water sensitivity and vulnerability maps have been prepared for
aquifers, watersheds, counties, regional areas and even states. It is very important that the scale of
the data available for the assessment be compatible with the area to be assessed and the scale of
the resulting map products.
Ground-water or aquifer sensitivity and vulnerability assessments can be important tools for
land-use planners and water resource managers. Sensitivity maps can help determine the most
hydrogeologically acceptable setting for specific land-use activities (e.g., waste disposal, siting of
industrial and commercial facilities, agricultural land uses, and urban land uses). Sensitivity and
vulnerability maps can also help:
• prioritize ground-water protection and remediation activities,
• prioritize areas for monitoring,
* insure efficient allocation of resources for clean up and restoration,
• point out special hydrogeologic characteristics that may influence clean up efforts,
and
• evaluate land-use activities to aid in development of pollution liability insurance.
Ground-water or aquifer sensitivity and vulnerability assessments are not intended to replace
site-specific investigations. Specific land-use and planning decisions should be made only after
considering site-specific hydrogeologic data and information such as the potential
contaminant(s), potential exposure pathways, and population at risk.
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IL GROUND-WATER OCCURRENCE AND USE IN EPA
REGION 8
II.A. MAJOR AQUIFERS AND AQUIFER SYSTEMS
The United States Geological Survey (USGS) and the State Geological Surveys have delineated,
mapped and characterized the major aquifers and aquifer systems in each of the Region 8 states
(USGS 1988). Well-maintained data on the development and use of ground water from these
aquifers will help assure sound management of the resource. Data should include the sensitivity
and vulnerability of the aquifers to contamination, and water quality trends within the aquifers.
Tables 1 through 6 include information on geology and water quality for the major aquifers and
aquifer systems within each Region 8 state. Figures 7 through 12 are maps of the major aquifers
and aquifer systems within each of the Region 8 states. There are numerous USGS and State
Geological Survey reports and publications that provide very detailed information on the
geology, hydrology and water quality for the aquifers and aquifer systems included in the tables
and maps. This report provides only a summary of the major aquifers and aquifer systems.
The USGS Ground Water Atlas of the United States provides more detail on ground water in all
states in EPA Region 8 (Robson and Banta, 1995) and (Whitehead, 1996).
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TABLE 1
MAJOR AQUIFERS/AQUIFER SYSTEMS IN COLORADO
Major Aquifers and
Aquifer Systems
Geology and Water Quality
Arkansas Valley-Fill
Aquifer
Unconsolidated, fluvial deposits in a 1-5 mile band along Arkansas
River and tributaries. TDS often high, sulfate commonly exceeds
SMCL.
South Platte Valley-
Fill Aquifer
Unconsolidated fluvial deposits underlying 4000 square miles
along South Platte River and tributaries. Nitrate commonly exceeds
MCL.
High Plains Aquifer
Unconsolidated to semi-consolidated fluvial deposits. Underlies
13,000 square miles in northeast Colorado. Locally sulfate exceeds
SMCL.
San Luis Valley
Aquifer System
Very thick Unconsolidated to semi-consolidated fluvial and
volcanic basin-fill deposits. Shallow unconfined aquifer < 130 feet
thick and lower confined aquifer several thousand feet thick
Denver Basin Aquifer
System
Four bedrock aquifers (Laramie-Fox Hills, Arapahoe, Denver &
Dawson) within a 3,200-foot thick sequence of Mesozoic
sedimentary rocks. Laramie-Fox Hills underlies 6300 square miles.
TDS increases in lower aquifers, sulfate is high along aquifer
margins; hydrogen sulfide and methane occur locally in deeper
parts.
Piceance Basin Aquifer
System
Two important aquifers underlie 1600 square miles northeast of
Grand Junction. Upper aquifer includes stream valley alluvium,
the Uinta Fm. and upper part of Green River Fm., lower aquifer is
middle part of Parachute Creek member of Green River Fm, TDS,
sodium, fluoride, boron and lithium increase with depth. Nitrate,
calcium, magnesium and sulfate decrease with depth.
Leadvi lie Limestone
Aquifer
Underlies much of northwest Colorado, Flow controlled by
fractures and solution openings, many springs discharge from
aquifer. Below 1000 feet TDS concentrations increase significantly.
Source: USGS (1988)
MCL is a Primary Maximum Contaminant Level. It is risk-based and enforceable under the Safe Drinking Water Act. It is the maximum
permissible level of a contaminant in water which is delivered to any user of a public water system.
SMCL is a Secondary Maximum Contaminant Level. This is not an enforceable standard, but a guideline based on taste, odor or appearance.
TDS is Total Dissolved Solids, a measure of the salts in the water. The SMCL for TDS is 500 mg/L.
16
-------
~!
PRINCIPAL AQUIFER AND SUBDIVISIONS
UNCONSOLIDATED SEDIMENTARY ROCK AQUIFERS
South Platte alluviaf (1)
Arkansas alluvial (2-4)
Alluvium of Arkansas River (2)
Alluvium of Fountain Creek (3)
Alluvium of Black Squirrel Creek (4)
High Plains
San Luis Valley aquifer system
Unconfined
Confined
CONSOLIDATED SEDIMENTARY ROCK AQUIFERS
Denver Basin aquifer system
Dawson
Denver
Arapahoe
Laramie-Fox Hifis
Ptceance Basin aquifer system
Upper aquifer, upper part
Upper aquifer, intermediate part
Upper aquifer, lower part
Lower aquifer
Leadvtlle Limestone
Other -- Dakota, Morrison, Entrada
[ j Not a principal aquifer
A—A' Trace of hydrogeologic section
Figure 7. Map of Major Aquifers in Colorado (Modified from USGS, 1988)
17
-------
TABLE 2
MAJOR AQUIFERS/AQUIFER SYSTEMS IN MONTANA
Major Aquifers and
Aquifer Systems
Geology and Water Quality
Cenozoic Aquifers
Western alluvial and basin-fill deposits. Occur primarily
along streams, mostly unconfined, TDS generally < 500
mg/1.
Western glacial deposits. Glacial till and glaciolacustrine
deposits, generally a few hundred feet thick.
Eastern alluvial deposits and terrace deposits. Generally
unconfmed, most productive aquifers in eastern Montana,
TDS generally > 1000 mg/1.
Eastern glacial deposits. Includes several units, generally
unconfmed.
Fort Union Formation. Includes several members of Ft.
Union, ground water occurs under confined and
unconfmed conditions, flow is toward local or major
surface drainages, TDS commonly > 1000 mg/1.
Mesozoic Aquifers
Hell Creek/Fox Hills. Includes basal sandstone of Hell
Creek Fm and underlying Fox Hills Fm., water is both
confined and unconfmed, TDS generally < 1000 mg/1.
Judith River Formation. Water is both confined and
unconfmed.
Eagle Sandstone. Water is both confined and unconfined,
TDS commonly > 2000 mg/1.
Kootenai. Confined conditions predominate, TDS
commonly < 1000 mg/1.
Ellis Group. Includes several formations, water is both
confined and unconfined.
Paleozoic Aquifer
Madison Group. Includes several formations but Madison
Limestone is primary aquifer, typically deep, TDS
increases away from outcrop.
Source: USGS (1988)
SMCL is a Secondary Maximum Contaminant Level. This is not an enforceable standard, but a guideline based on taste, odor or appearance.
TDS is Total Dissolved Solids, a measure of the salts in the water. The SMCL for TDS is 500 mg/L.
18
-------
PRINCIPAL AQUIFER AND SUBDIVISIONS
10 CENOZOIC AdUlFERS (1-31
Western alluvial am! basin-fill deposits (1)
Western glacial deposits
Eastern alluvial deposits and terrace gravels (2)
Eastern glaciai deposits
Fort Union Formation (3f
; I MESQ201C AQUIFERS (4-7)
Kell Creek Formation srxi Fox Hills Sandstone (4]
Judith River Formation (51
Eagle Sandstone |6t
Kootenai Formatiori (71
Ellis Group
r^l PALEOZOIC AQUIFER (8i
Madison Group (8!
r"l Not 3 priacipal aquifer
A—A' Trace of hydro geologic section
Southern border of continental giaciation
Figure 8. Map of Major Aquifers in Montana (Modified from USGS, 1988)
19
-------
TABLE 3
MAJOR AQUIFERS/AQUIFER SYSTEMS IN NORTH DAKOTA
Major Aquifers and
Aquifer Systems
Unconsolidated aquifers
Fort Union Aquifer
System
Hell Creek-Fox Hills
Aquifer System
Dakota Aquifer System
Madison Group Aquifer
Geology and Water Quality
Includes surficial and deep glacial aquifers and stream alluvial
aquifers, often hydraulically connected to underlying bedrock
aquifers, IDS greater in deeper aquifers
Uppermost bedrock aquifer system, variable extent and thickness,
yield and quality is variable
Hell Creek/Fox Hills, Includes basal sandstone of Hell Creek
Formation and underlying Fox Hills Formation. Water is both
confined and unconfined. Occurs in central and western ND,
dependable yields.
Underlies most of state but water too saline in west, use restricted
primarily to livestock watering in southeast part of State.
Aquifer is very deep, high IDS, and not used
Source: USGS (1988)
TDS is Total Dissolved Solids, a measure of the salts in the water.
20
-------
PRINCIPAL AQUIFER
^B UnconsolkJated aquifers 11-6}
Fort Union aquifer system
Hell Creek-Fox Hills aquifer system (7)
Great Plains (Dakota} aquifer system
Madison Group
Ordovician and Precambrign rocks
A—A' Trace of hydrogeologic section
Figure 9. Map of Major Aquifers m North Dakota (Modified from USGS, 1988)
21
-------
TABLE 4
MAJOR AQUIFERS/AQUIFER SYSTEMS IN SOUTH DAKOTA
Major Aquifers
and Aquifer
Systems
Geology and Water Quality
Glacial-Drift and
Alluvial Aquifers
Occurs mostly in eastern half of state, predominantly glacial outwash and
stream alluvial deposits, some buried outwash aquifers, locally nitrate
exceeds MCL.
High Plains Aquifer
Occurs in south-central South Dakota, composed of unconsolidated and
slightly consolidated sandstone in Ogallala and Arikaree Formations, 90%
of use is for irrigation, locally selenium exceeds MCL.
Fort Union, Hell
Creek and Fox Hills
Aquifers
Occur primarily in northwest part of State, composed of very fine
sandstone, generally confined, locally selenium and molybdenum
concentrations are high.
Niobrara-Codell
Aquifer
Occurs in eastern South Dakota, composed of shale, chalk, and fine-grained
sandstone, water is slightly saline.
Dakota-Newcastle
Aquifers
Underlie most of State, generally confined and composed of sandstone
interbedded with shale and siltstone, primarily used for livestock watering.
Water is slightly to moderately saline, IDS typically exceeds 2000 mg/1
except in southeast part of State.
Inyan Kara,
Sundance,
Minnelusa, Madison
Red River and
Deadwood Aquifers
Aquifers are confined over most of extent, development limited mainly to
the area near the Black Hills, elsewhere development limited by great depth.
Composed of interbedded sandstones, siltstones, limestones and shales.
Fluoride concentrations commonly exceed MCL of 2 mg/L; radium 226 and
gross alpha exceed MCL in parts of Madison and Inyan Kara-
Source: USGS (1988)
MCL is a Primary Maximum Contaminant Level, It is risk-based and enforceable under the Safe Drinking Water Act. It is the maximum permissible
level of a contaminant in water which is delivered to any user of a public water system.
SMCL is a Secondary Maximum Contaminant Level. This is not an enforceable standard, but a guideline based on taste, odor or appearance.
TDS is Total Dissolved Solids, a measure of the salts in the water. The SMCL for TDS is 500 mg/L.
22
-------
PRINCIPAL AQUIFER AND SUBDIVISIONS
GIA&AL-DHIFT AND ALLUVIAL ACMIKRS
Major glacial-drift aquifers
SEDIMENTARY BEDROCK AQUIFERS
C"j High Wains aquifer
Fort Union-Hell Creek-Fox Hills aquifers
Niobrara-Codell and Dakota-Newcastle aquifers
Dakota and Newcastle
Typel
Type 2
Inyan Kara, Sundance. Minneiusa. Madison,
Red River, arid Deadwood aquifers
Inyan Kara, Sundance, Minnefusa, and Madison
Typel
Type 2
CONFINING UNITS AND BASEMENT ROCKS
E3 Shale
[ 1 Not a principal aquifer
A—A' Trace of hydrogeologic section
Figure 10. Map of Major Aquifers in South Dakota (Modified from USGS, 1988)
23
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TABLES
MAJOR AQUIFERS/AQUIFER SYSTEMS IN UTAH
Major Aquifers and Aquifer
Systems
Geology and Water Quality
Unconsolidated Basin-Fill and Valley-
Fill Aquifers
Occur in 12 intermontane valleys in western Utah.
Recharge areas are near mountain fronts and discharge
occurs to lakes and playas in central portion of basins.
IDS generally less than 1000 mg/L, higher near
discharge areas.
Sandstone and Carbonate Rock
(Colorado Plateau Aquifers)
Underlie thousands of square miles in southeast Utah.
TDS in the sandstones generally less than 1000 mg/L in
the recharge area, increasing downgradient with depth.
Carbonate aquifer not extensively used.
Source: USGS (1988)
SMCL is a Secondary Maximum Contaminant Level. This is not an enforceable standard, but a guideline based on taste, odor or appearance.
TDS is Total Dissolved Solids, a measure of the salts in the water. The SMCL for TDS is 500 mg/L.
24
-------
•:- s i rl
... • .-..^.a.-: .=--.-j^^.-.-..:.!'is.Mv=.-..-J!
AQUIFER AMD SUBDIVISION
UNCOHSOLIDATtD BA*jWi^l,L AQUIFERS
Curtaw Valluv <1?
Caste Vallev «l
East Shdra arfta (3)
Sail Lake Valtay (4}
Tcalc V«lfty CSi
UMt^ and GoShen Valtevs ffl[
Northern. 'Utah W»]
i*- Deawi [flj
ur.t Valkry (S(
(tt)
Cedar Vsl
UNCONSOLIOATED
SANDSTONE AQUIFERS
HOCK.
^i4t ft principal
Boundary «f squffer
Figure 11. Map of Major Aquifers in Utah (Modified from USGS, 1988)
25
-------
TABLE 6
MAJOR AQUIFERS/AQUIFER SYSTEMS IN WYOMING
Major Aquifers and
Aquifer Systems
Geology and Water Quality
Alluvial Valley-Fill
Aquifers
Occur in valleys and terraces of most large streams in Wyoming and
are generally less than 50 feet thick, T0S generally less than 1000
mg/L, selenium exceeds MCL in some irrigated areas.
High Plains and Equivalent
Aquifers
Consist of semi-consolidated sands and gravels and occur in the
southeast part of the State. IDS concentrations generally less than
500 mg/L, nitrate exceeds MCL in some agricultural areas.
Sedimentary Aquifers in
Structural Basins
Extensive beds of sandstone, coal and shale comprise shallow
aquifers within the 13 structural basins in Wyoming. These are the
most widespread and most extensively-used aquifers in terms of
numbers of wells. Thickness may reach 5000 feet. TDS
concentrations typically greater than 500 mg/L.
Carbonate and Sandstone
Aquifer System
Also occurs in 13 structural basins, exposed along mountain fronts
and buried deeply away from mountain fronts. Thickness may be
several thousand feet. TDS is generally low in outcrop areas and
higher where buried deeply.
Source: USGS (1988)
MCL is a Primary Maximum Contaminant Level. It is risk-based and enforceable under the Safe Drinking Water Act. It is the maximum permissible
level of a contaminant in water which is delivered to any user of a public water system.
SMCL is a Secondary Maximum Contaminant Level. This is not an enforceable standard, but a guideline based on taste, odor or appearance.
TDS is Total Dissolved Solids, a measure of the salts in the water. The SMCL for TDS is 500 mg/L.
26
-------
PRINCIPAL AQUIFER
I. -•! High Plains and equivalent aquifers
["ZLJ Structural basin
t:v;-J Carbonate and sandstone
["";~j Not a principal aquifer
A—A' Trace of hydrogeologic section
Figure 12. Map of Major Aquifers in Wyoming (Modified from USGS, 1988)
27
-------
ILB. GROUND WATER USE
Irrigating crops
and watering
livestock
account for
approximately
75% of total
ground-water
use across the
Region.
Potable water
for public water
supplies and
private
domestic uses
account for
another 17%.
In 1995, more than 3.8 billion gallons of fresh water were withdrawn every
day for human use in Region 8 (Table 7). Agriculture and public and
private domestic water supply are the most common uses across the Region.
Irrigating crops and watering livestock account for approximately 75% of
total ground-water use across the Region. Public and private domestic
water supply accounts for another 17% (see Figure 2). Other important uses
of ground water include direct use by industry, mining, and thermoelectric
power generation (Figure 2).
While the top two use categories are the same in all Region 8 states, total
withdrawal and use varies considerably (Table 7). For example, in 1995 an
estimated 204 million gallons of fresh ground water were withdrawn per day
in Montana. About 40% was used for irrigation. By contrast, daily
withdrawals in Colorado were more than 10 times greater, and 90% was
used for irrigation. More ground water is withdrawn for public water supply
uses in Utah than in all of the other five states in the Region combined.
Daily withdrawals for public water supply use in Utah were roughly 293
million gallons per day (mgal/day) in 1995. This is almost three times the
amount used in the next highest state, Colorado.
Agricultural Use
Agricultural use is the predominant use of ground water in all six Region 8 states. Irrigated
agriculture accounts for 73% of the total ground-water withdrawn across the Region (Figure 2), which
is approximately 2.8 billion gallons per day (Table 7), Approximately 2 billion gallons of ground
water per day were used to irrigate crops in Colorado alone. This accounts for 90% of ground-water
use in this state.
Agricultural withdrawals vary significantly from year to year, as shown by USGS water use data from
1985,1990 and 1995 (Figure 13). Irrigation withdrawals were highest Region-wide and in five of six
states during 1990. The most important factor influencing ground water use for irrigation is the
amount of water available from precipitation and runoff during the growing season. During years
when surface water and precipitation is less available, a larger proportion of the water used for
agriculture is withdrawn from the ground. For example, use of ground water for irrigation in South
Dakota increased from 85 million gallons per day in 1995 to approximately 137 million gallons per
day in 2000 (Amundson 2002), while other uses remained relatively constant. Changes in irrigation
techniques to conserve water have contributed to declines seen between 1990 and 1995 in Figure 13
(Solley and others, 1998).
28
-------
TABLE 7
FRESH GROUND-WATER WITHDRAWALS BY WATER-USE CATEGORY AND STATE
1995
Million Gallons per Day
USES
Public Supply
Private Domestic
Commercial
Irrigation
Livestock
Industrial
Mining
Thermoelectric
TOTAL
.COLORADO
100
27
7.7
2,020
23
37
25
22
2,260
MONTANA
y 1-. * .
„ ^ V' ' " " «.
2- -v '
55
17
0
82
16
31
2.8
0
204
NORTH ,
DAKOTA i
30
12
0.1
59
14
3.6
3.8
0.3
123
•' SOtJTH
DAKOTA
53
9.3
6.1
85
18
4.1
7.8
3.4
187
UTAH
293
7.7 '
3.8
393
7.6
55
16
0
776
WYOMING
38
9.7
0.9
181
13
1.6
71
1.0
316
TOTALSx
."' *" „ * '^'til, £ "" 1
569
82.7
18.6
2,820
91.6
132.3
126.4
26.7
3,866
SOURCE: (Solley and others 1998, page 15). Figures may not add to totals because of independent rounding.
29
-------
Figure 13. Irrigated Agricultural Use
in Region 8 by Year
3000
2500
>> 2000
1 1500
O)
^ 1000
500
1985
1990
1995
CO MT ND SD
State
UT WY
Source: Solley and others, 1998
30
-------
Public Water Supply and Private Domestic Water Supply Use
No matter where they live, people need access to clean, safe water in and around their homes. This
water is used to meet many needs, such as drinking, cooking, bathing, flushing toilets, and watering
landscapes. Throughout Region 8, ground water is a major source of water for these uses. People
receive their water either from public water supplies, which serve 25 or more persons, or private
domestic water supplies, usually wells, which serve fewer people. Private domestic wells may serve
only a single home. Approximately 3.5 million people across the Region relied upon ground water in
1995 (Solley and others, 1998). Public water supply and private
domestic water supply combined form the second largest use of ground
water for all six states; roughly 650 million gallons were used every day
in 1995 (Table 7). This table also shows a state-by-state breakdown of
the volumes of ground water withdrawn for both uses. Utah consumes
the most ground water for these purposes; withdrawals for public and
private domestic water supply combined were more than 300 million
gallons per day.
Ground water is an
important source
for public and
private domestic
water supply uses
in every state in
Region 8, providing
for over 3.5 million
people across the
Region in 1995
(Solley and others,
1998).
Public Water Supply
Public water supply is the second largest use of ground water in the
Region by volume. This use accounts for approximately 15% of total
usage (Figure 2), or 569 million gallons per day in 1995 (Table 7).
There are different kinds of public water systems. Most familiar is the
community water system, which serves people in their homes. The
remaining kinds of water systems serve the public where they work, go
to school, or at places such as rest stops and camp grounds. All commonly use ground water as their
source of supply. Approximately 75% to 90% of public water systems in each state in Region 8
depended on ground water to serve people in their homes, at work, or at play in the year 2000 (Figure
14).
hi Region 8, community water systems serving 100,000 or more people typically rely on surface
water for their source. However, most other community water systems rely on ground water
(USEPA, 2001a). More than 2.6 million people in Region 8 relied solely on ground water supplied
by community water systems for drinking, bathing, cooking, and watering their lawns in the year
2000. Another 2.2 million people in Region 8 got their water from community water systems that use
both ground water and surface water, in the year 2000. (Hutchinson, 2002)
Trends in ground-water use for public water supply have been highly variable from state-to-state from
1985 to 1995 (Figure 15). Colorado has seen a marked increase in ground-water withdrawals for
public water supply. In general, other states have generally held steady or declined. While new
public water systems using ground water have been created in each state during this time period,
others have switched over to surface water, often in conjunction with consolidation of smaller public
water systems into larger, regional systems. This has created variable trends among the states as seen
31
-------
"c
CD
O
i_
ed Public Water Supplies by State
• __Hi_
: : i
I
i i
:
: ; I
! . I
' i :
;
i
•
• Percent PWSs Using
GW
CO ND UT
MT SD WY
State
Source: USEPA2001a
32
-------
Figure 15. Public Water Supply Use
in Region 8 by Year
CD
CD
O)
300
200
100
0
1985
1990
1995
CO MT ND SD UT WY
State
Source: Solley and others, 1998
33
-------
in Figure 15. Notably, over the period from 1985 to 1995 there was also a decrease in per capita
water use, the first such decrease since 1950 (Solley and others, 1998).
Private Domestic Water Supply
People living outside of established urban or suburban areas commonly have private wells for their
domestic water needs. Water use information derived from Public Water Systems does not include
ground-water use from private springs and wells. Approximately 1 million people in the Region
relied on ground water from private wells for drinking, bathing and other domestic uses in 1995. The
number of people using private wells varies considerably from state-to-state; Figure 16 shows the
estimated population served in each state by private domestic wells over the decade from 1985-1995.
The rural population, using private wells, has increased notably in Colorado, Utah, and Montana from
1990 to 1995. Population growth in rural areas results in more and more residents relying on their
own wells to provide water. For example, in Colorado private domestic withdrawals increased by
about 60% over this time from 17 mgal/day to about 27 mgal/day (Solley and others, 1998).
Ground-Water "Mining"
There are large volumes of ground water in Region 8. However, the quality of the water stored in the
aquifers, and the ease with which it may be withdrawn, limits the use of these resources. The amount
of ground water available to wells at any given time is based on complex processes involving
hydrology, climate and geology. Natural fluctuations in water levels are common in aquifers. These
generally depend on a balance between discharge and recharge to maintain levels within a certain
range. Human activities can affect ground-water levels, particularly when withdrawals exceed the
natural recharge rate of an aquifer or portion of an aquifer.
The term ground-water "mining" or overdraft describes situations where withdrawals and net
discharges from an aquifer exceed the rate of recharge. Individual aquifers, or portions of aquifers,
that are being depleted at rates greater than natural recharge are common across the Region. For
example, declines in water levels between 1940-1980 in the heavily used High Plains Aquifer are
more than 100 feet in many areas. Since 1980, advances in
irrigation technology, such as the use of center pivot irrigation
systems, and improved management practices have reduced
ground-water pumpage throughout much of the aquifer. This
has slowed the rate of water-level decline, but overdraft
conditions still exist. The cost of drilling new, deeper wells in
areas of water-level decline can often become economically
prohibitive. Thus, the depletion of aquifer levels is a growing
problem in areas such as Douglas County, Colorado and Salt
Lake City, Utah, and in some agricultural areas.
34
-------
Figure 16. Rural Domestic Ground Water Use
Estimated Population using Ground \Afoter
from Rural Domestic Wells and Springs
4OOOOO
350000
3OOOOO
~ 250000
jflB
3
g- 200000
CL
150000
1OOOOO
50000
CO
•
MT
<>
ND
—&—
SD
"•**^i"in
UT
T
WY
1985
1990 1995
Source: Solley and others, 1998
35
-------
The impacts of these overdrafts are becoming increasingly apparent. Many wells on the edges of the
Denver Ground Water Basin south and east of Denver are beginning to dry up due to extensive
development. Elsewhere, overdrafts and consequent water-level declines are impacting stream flow
in rivers such as the Arkansas River in Colorado. In Montana, the State Engineer closed 23 basins
from additional surface water withdrawals. Five of these basins are also closed to additional ground-
water withdrawals, in order to maintain streamflows sufficient for basic ecological functions.
The ground-water use data discussed in section ILB of this report do not include data for the year
2000. The USGS is currently compiling data for ground-water use in each of the 50 states for the year
2000. The data summary, expected to be available as a USGS report in 2003, will be used to update
this report. During the interim period, information on ground-water use in the Region 8 states can be
obtained from State Engineers Offices and local USGS offices.
36
-------
III. GROUND-WATER QUALITY IN REGION 8
III.A. NATURAL GROUND-WATER QUALITY
Natural ground-water quality varies between and within aquifers, depending on such factors as the
type of rock or sediment through which the water flows and local biological and chemical conditions.
Freeze and Cherry (1979, Chapters 3 and 7) and Hem (1985) offer good discussions of natural water
quality.
Total dissolved solids (IDS) concentrations reflect the amount of dissolved minerals found in water.
TDS is primarily the result of chemical interactions between ground water and the rocks or sediments
through which the water moves. Sodium, magnesium, calcium, chloride, bicarbonate, and sulfate
make up more than 90% of the TDS in uncontarninated water (Freeze and Cherry, 1979). In some
areas in Region 8, the use of ground water for human consumption and agricultural purposes is
limited by high TDS.
EPA has set a recommended TDS standard of 500 mg/L (parts per million) for drinking water. The
500 mg/L standard is a secondary standard for public water supplies. It is not an enforceable
standard, but a guideline based on taste, odor, or appearance. Concentrations above 1,000 mg/L are
not uncommon in aquifers in each of the Region's states. For example, on the Fort Peck Tribal
Reservation in Montana, ground water with TDS greater than 1,000 mg/L is sometimes consumed.
Surface waters are not dependable because of scanty and erratic precipitation. Shallow ground water
is available on most of the Reservation; however, where it is found, it is often of poor quality. In
addition, the ground water in the confined bedrock aquifers underlying the Reservation is not a highly
developed source because of high to very high salinity and other mineral content. Of a sampling of
wells in select areas on the Reservation, all wells greater than 100 feet deep had TDS greater than
lsQOOppm.
The amount of TDS in ground water is important for management of the resource because most State
ground-water classification schemes are based on TDS (see section 3Y.B).
Other naturally-occurring constituents in ground water include potassium, iron, manganese, fluoride,
arsenic, and radon. In high concentrations, these substances may stain fixtures, cause incrustations to
develop on pipes and fixtures as solids precipitate, affect the taste and color of water, and may
adversely affect human health. Some aquifers in the Region contain water that exceeds EPA drinking
water standards for some of these constituents (see tables in Section n.A). High naturally-occurring
concentrations of fluoride, for example, are common in the bedrock aquifers in western South Dakota.
37
-------
III.B. CONTAMINATION AND THREATS TO GROUND WATER
Human activities associated with agricultural, mining, industrial, rural and urban land uses affect
ground-water quality in Region 8. Ground-water contaminants include a variety of organic and
inorganic constituents including nutrients (e.g., nitrate, phosphate), volatile organic compounds (e.g.,
benzene, solvents), pesticides, metals, dissolved solids, bacteria, and viruses. Examples of human
activities that can impact ground-water quality are summarized in the following sections. For a
comprehensive discussion of all sources of ground-water contamination, see USEPA (1990).
Sources of Ground-Water Contamination
Each State in Region 8 is required by the Clean Water Act Section 305(b) to submit a report about
water quality every two years. Ground water was included in these reports for the first time in the
year 2000 report from each state.
Each report has a summary of selected potential sources of ground-water contamination, which
include point sources and non-point sources. The significance of the sources is ranked by:
• the number of source types;
the location of sources relative to ground water withdrawn for human consumption and
agricultural purposes;
the size of population;
• relative risks posed to humans;
• the hydrogeologic sensitivity or vulnerability of specific aquifers; and
the findings of state and federal ground-water monitoring efforts.
Table 8 summarizes the most problematic contaminant sources. Each state report is referenced
below.
Colorado. "Status of Water Quality in Colorado 2000", October 2000, Prepared by the Water
Quality Control Division with assistance from Mesa Technical Consultants.
North Dakota. "North Dakota Water Quality Assessment, 1998-1999. The 2000 Section
305(b) Report to the Congress of the U.S.", by the North Dakota Department of Health,
Division of Water Quality, Bismarck, ND.
South Dakota. <(The 2000 South Dakota Report to Congress, 305(b) Water Quality
Assessment, Water Years 1995-1999", Prepared by South Dakota Department of
Environment and Natural Resources, Pierre, South Dakota.
Montana. "Montana Water Quality 1998". 305(b) Report.
38
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Utah. "Utah Water Quality Assessment Report to
Congress 2000", Division of Water Quality,
Department of Environmental Quality, September
2000.
Wyoming. "Wyoming's 2000 305 (b) State Water
Quality Assessment Report", Wyoming Department of
Environmental Quality, April 2000.
The most commonly
cited sources in
Region 8 are: animal
feedlots, underground
storage tanks, surface
impoundments, septic
systems, large
industrial facilities,
and spills.
39
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TABLES
SOURCES OF GROUND-WATER CONTAMINATION BY STATE
Agricultural
Activities
Ag chem facilities
X
X
X
Animal feedlots
X
X
Drainage wells
Fertilizer applications
X
X
Cropping and
irrigation practices
Pesticide applications
On-farm agricultural mixing
and loading procedures
X
Land application
Material Stockpiles
Storage tanks (above ground)
X
X
X
Storage tanks (below ground)
X
X
X
X
Surface impoundments
X
X
X
X
Waste piles
Waste tailings
40
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TABLE 8 (continued)
SOURCES OF GROUND-WATER CONTAMINATION BY STATE
CONTAMINANT
•SOURCE
Disposal Activity
Deep injection wells
Landfills
Septic systems
Shallow injection wells
Other
Hazardous waste generators
Hazardous waste sites
Large industrial facilities
Material transfer operations
Mining and mine drainage
Pipeline and sewer lines
Salt storage and road salting
Salt water intrusion
Spills
Transportation of materials
Urban runoff
Saline seeps
Small scale manufacturing
and repair shops
COLORADO, ,
X
X
X
X
X
X
X
MONTANA
X
X
X
X
X
NORTH
DAKOTA
X
X
SOUTH
DAKOTA
X
X
X
X
UTAH s
X
X
X
X
. WYOMING
X
X
X
SOURCES: State 305(b) reports except for Wyoming. For Wyoming, personal communication with Kevin Frederick, WDEQ.
41
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Agriculture
Agricultural activities, such as irrigated crop farming, grazing and livestock production, are one of the
most widespread sources of ground-water contamination in the Region,
The most common contaminant is nitrate. Other common
contaminants are sediments, nutrients and pesticides. Nitrate levels
above the lOmg/L drinking water standard set by the EPA can have
both long and short-term health effects. Nitrate is particularly
dangerous to infants because it can cause "blue baby syndrome"
(methemoglobenemia). Documented cases in Region 8 include a
death of a baby in South Dakota in 1965 (Virgil, 1965).
Irrigated agriculture can contribute to elevated nitrate levels in
aquifers when inorganic and organic fertilizers leach into ground
water. Dissolved solids and salinity may increase in ground water
and surface water when water is reused many times for irrigated
agriculture (Figure 17).
Pesticides and their associated metabolites (breakdown by-products)
are also a concern in agricultural areas in Region 8. Even with the relatively low use of pesticides,
pesticides occur in ground water and surface water in every state (Reetz, 1998). Although detections
of pesticides above EPA drinking water standards are uncommon, the human impacts of many of
these pesticides and their metabolites are poorly understood and monitoring for them is very limited.
These compounds may be a future concern if they persist and accumulate in ground water. In a 1996
assessment conducted by EPA, the most frequently detected pesticides in ground water in 19 western
states included the fumigants ethylene dibromide (EDB) and 1,2 dichloropropane; the insecticides
aldicarb, carbofuran, and chlordane; and the herbicides alachlor and atrazine (Reetz, 1998).
Extrapolating this information for Region 8 is difficult, but the available data indicate that some of
these contaminants are also found in the Region.
For example, in Teller County, Colorado, high levels of EDB were detected in five municipal supply
wells in 1994. During the 1960s and 1970s, a pesticide containing EDB was used extensively in the
area to help control the pine beetle. EPA conducted site investigations from 1996 to 1999 to
determine the source of the EDB and its distribution in the aquifer. The source was identified and
eliminated, and a monitoring system was established, as well as a treatment system for the EDB.
42
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Urine and Manure
Crop
Residues
Flxat:on
Votati!'—n
Fertilizer
Organic N
Mineralization
Nitrification
Croo Uptake
Figure 17. Nitrate in Ground Water
43
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Improperly managed animal feedlots generate large amounts of waste that can result in increased
concentrations of certain pollutants in ground water. There are about 238,000 animal feeding
operations (AFOs) in the U.S., including livestock (such as beef and swine) and poultry, AFOs are
agricultural enterprises where animals are kept and raised in confinement. AFOs annually produce
more than 500 million tons of animal manure. This compares to EPA estimates of about 150 million
tons of human sanitary waste produced annually (assuming a population in the U.S. of 285 million
people). By this estimate, all confined animals generate three times more raw waste than is generated
by humans in the U.S. (USEPA 2003). AFOs can pollute surface water and ground water with
nutrients (nitrogen and phosphorus), organic matter, solids, pathogens, salts, metals, pesticides,
antibiotics, and hormones. Pollutants enter ground water by leaching from lagoons and stockpiles,
through spills, and leaching from cropland after application of manure.
44
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Mining
Past and present mining activities, though closely associated with surface-water contamination, are
also a source of ground-water contamination in Region 8. In the Rocky Mountains, there are
hundreds of large active mines and tens of thousands of inactive mine sites (Reetz, 1998). Some of
these sites are serious enough to be included in the Superfund program, such as the Kennecott mine in
Utah and the Summitville mine in Colorado. Approximately one half of the Superfund sites in
Region 8 are related to mining. Nine of the top eighteen mine-impacted watersheds in the nation are
in Region 8, eight of which are in Colorado (Reetz, 1998).
Types of sources at hardrock mining sites include: mine waste such as waste rock and tailings;
underground workings; and processing facilities such as leach pads and mills. Ground-water
contamination at hardrock mine sites occurs as a result of physical and chemical interactions between
exposed ore bodies, water, air, and microorganisms. In areas where coal or metallic ores have been
mined, precipitation that falls on and percolates into mill tailings or waste rock can oxidize sulfide
minerals. This results in low-pH (acidic) water which can dissove metals and transport them into
underlying ground water. This mineralized water can move into wells or surface streams and ponds.
Large concentrations of arsenic, copper, iron, zinc, lead, manganese, radium, selenium, and sulfate
can result from the leaching of sulfide-rich mill tailings and can contaminate large areas of aquifers.
Since this oxidization process can continue for hundreds of years, remediation of such sites is an
expensive and long-term process.
For example, the Leadville Mining District is a very large hardrock mining district
located in Lake County, Colorado. Silver mining continued until 2002 when the last
operating mine closed. Within the Leadville District, the ore was mined by underground
methods. A number of mine adits and shafts currently discharge water from the mine
pool (ground water). The mine waste and draining adits and shafts comprise the most
serious sources of contamination. High concentrations of heavy metals such as zinc and
copper in streams that drain the District and in the Arkansas River present a significant
risk to aquatic life. In 1983 a large part of the District was listed on the National
Priorities List, regulated under CERCLA. As part of the remedy, two large water
treatment plants are currently being operated to treat adit discharge. One of the current
priorities under CERCLA is to develop a remedy for contaminated ground water. This
will require a more detailed characterization of the mine pool(s) and more detail on the
magnitude of heavy metals loading to the Arkansas River via ground water. As with
many hardrock mining sites it will be necessary to continue operation of the mine waste
and water treatment remedies for many decades into the future.
45
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Underground Storage Tanks
Most states in Region 8 report that leaking underground storage tanks (USTs) are a high-priority
source of ground-water contamination (Figure 18). USTs are generally found in urban and
suburban areas. They are primarily used to store petroleum products that contain volatile organic
compounds such as MTBE (a gasoline additive), benzene, toluene, ethylbenzene and xylene
(BTEX compounds). There are thousands of USTs across the Region. Montana, for example,
indicates that there have been nearly 1,000 confirmed releases from USTs and that half of these
have impacted ground water (personal communication, John Arrigo, MDEQ). The impacts of
leaking tanks can be locally significant. MTBE and other additives are more mobile than the
BTEX compounds and can contaminate greater volumes of ground water.
Table 9 summarizes UST activities in each state in Region 8 as of early 2002. The table shows
confirmed releases, but this does not necessarily mean that ground water was impacted. The large
number of cleanups initiated compared to the number of confirmed releases shows the
preventative nature of the UST program with regard to ground water contamination.
Waste Disposal
Liquid and solid waste disposal is perhaps the best known source
of ground-water contamination and is locally significant across
the Region. Waste disposal includes a broad category of
activities and potential sources such as septic systems, landfills,
surface impoundments, waste injection wells, the application of
stabilized waste as fertilizer, and illegal dumping.
Shallow injection wells, such as septic systems, storm drains, dry
wells, and cesspools are locally important sources of ground-
water contamination in the Region. For more information on
this source, see www.epa.gov/safewater/uic/classv.html. By
volume, onsite sewage disposal from septic systems is the largest discharger to the subsurface in
the waste disposal categoiy (Figure 19). Unsuitable design and poor management of septic
systems can contaminate ground water, particularly when they are used to dispose chemical
wastes. Standard septic designs are particularly poor in thin soil and fractured rock settings that
are common in mountainous areas. Human wastes and nearly any household chemical poured
down the drain of a home served by a septic system can reach the local ground-water system.
Nitrate and bacteria are contaminants found in ground water in areas with a high density of septic
systems.
46
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Figure 18. Underground Storage Tank with Monitoring Well
47
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TABLE 9
OFFICE OF UNDERGROUND STORAGE TANKS
FY02 SEMI-ANNUAL ACTIVITIES
2002
,-::Di^^Q^:-{\]
Number of Confirmed
Releases
Number of
Cleanups
Initiated***
Number of Cleanups
Initiated
State Lead / TF $s
Number of Cleanups
Completed***
Number of Cleanups
Completed
State Lead / TF $s
Number of
Emergency
Responses
TOTAL
t<>LO^Aj>6
5,552
5,082
234
4,074
199
32
••>IO:NTA^A;
2,962
2,213
39
1,756
16
42
NORTH
lDAKJOTX::;f
812
811
15
754
14
3
&bUTR
:.0^K^fA:;;
2,257
2,139
12
1,731
2
18
UTAH
3,875
3,607
10
3,247
7
4
^:^^W^::^
1,963
949
120
496
6
61
&dv&fc$
17,421
14,801
430
12,058
244
160
Source: USEPA UST Access Database, 2002
***RP Lead and/or State Lead with State Money
48
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Transpiration
Runoff
Septic
Groundwater
movement
41 \V system leachate Wate^table
Evaporation
7mJ7T77T7m7T7777777777777777777777777777777777//////////////77r/
Bedrock
Figure 19. Septic Tank Schematic
-------
Oil and Gas Production
Oil and gas production activities arc also a potential source of ground-water contamination in localized
areas. These activities can contaminate ground water by a variety of mechanisms. Oil wells produce
brines (very salty waters) that are separated from oil and stored in surface impoundments. Seepage
from these impoundments and the brine wastewater that has been injected into wells can contaminate
ground water in addition to impacting surface waters and riparian habitat.
Over the past five years natural gas is being produced at significantly increasing rates in Colorado,
Wyoming, Montana, and Utah. Natural gas in these areas is produced by withdrawing large amounts
of ground water from geologic strata containing coal seams and methane. Coalbed methane (CBM) is
released when the water table is lowered. CBM production in southwest Colorado (San Juan Basin)
has raised environmental concerns by landowners and homeowners for over a decade due to apparent
effects caused by reinjection of produced water into deep aquifers.
Currently, CBM development in the Powder River Basin in Wyoming and Montana, is causing
concerns about surface-water and ground-water quality. For example, the ratio of sodium ions to
calcium and magnesium ions present in water, in part, dictates the suitability of that water for crop
irrigation. This ratio is known as the sodium-adsorption ratio (SAR). Elevated SAR values have been
reported for some coalbed methane ground waters. Introduction of higher SAR water from CBM
discharge into the Powder River has the potential to affect the use of water by irrigators downstream of
those CBM discharges. A prominent concern is the potential destruction of soils suitable for
agricultural use.
Hazardous Waste Sites
Accidental spills and poor waste management practices have contaminated a number of sites in Region
8 with hazardous substances. EPA administers the clean up and control of many of these hazardous
waste sites primarily under the authorities of the Resource Conservation and Recovery Act (RCRA)
and the Comprehensive Environmental Response Compensation and Liability Act (CERCLA or
Superfund). The RCRA Corrective Action program priorities are active facilities where poor waste
management and handling practices create risks due to human exposure and ground-water
contamination.
The Region's Superfund program has identified dozens of sites with known ground-water
contamination; at least 20 of the 52 active National Priority List (NPL) sites in Region 8 involve some
ground-water contamination issues. Contaminants affecting ground water at Superfund sites vary
depending on past activities. Common contaminants include cleaning solvents, petroleum products,
pesticides, PCB's, dioxins, acid rock drainage, metals, and radioactive materials. Ground-water
contamination at many of these sites is significant and requires complex and costly remediation
activities. For example, past mining and processing activities at the Kennecott South site in Copperton,
Utah have resulted in a plume of sulfate in the local aquifer that covers more than 77 square miles.
Along the South Platte River in South Denver, hexavalent chromium from a plating facility has
50
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contaminated ground water along a two-mile reach of the alluvial floodplain aquifer. Historical solvent
use and disposal at the former Lowry Air Force Base in the Denver area created a trichloroethylene
plume nearly two miles long in the water-table aquifer.
Urban and Suburban Sources
Urban and suburban land uses are also a locally significant source of ground-water contamination in
the Region. Spills and runoff from industrial areas and roadways, park and golf course maintenance
activities, fertilizer, pesticide and herbicide use on lawns and golf courses (Figure 20), fuel and solvent
use, and other activities collectively make urban nonpoint sources of contamination significant. In
addition, urban areas generally have higher concentrations of leaking storage tanks and hazardous
waste sites affecting ground water. Pesticides and other organic chemicals associated with petroleum
products and solvents are commonly detected in ground water in urbanized areas.
51
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Figure 20. Fertilizer, Herbicide, and Pesticide Use
On Lawns Can Contaminate Ground Water
52
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III.C. GROUND-WATER QUALITY MONITORING AND DATA:
STRENGTHS AND LIMITATIONS
Introduction
There is insufficient information available to effectively characterize the overall quality of ground
water in most Region 8 aquifers. Federal, State and local agencies have only recently begun to focus
their attention on monitoring ambient ground-water quality for analytes such as nitrates, volatile
organic compounds, and pesticides. Ground-water samples are relatively expensive to collect and
analyze. Furthermore, the data are not necessarily stored on a database available to others, or they may
never be entered on an electronic database. Inadequate funding for assessment and monitoring
prevents comprehensive understanding of the Region's ground water. Thus, many State monitoring
programs focus on the most heavily used aquifers and those that are considered most vulnerable to
contamination.
Currently, ground-water monitoring in Region 8 is conducted by a variety of Federal, State, and Tribal
programs. Federal efforts are primarily by the U.S. Geological Survey (USGS), the U.S.
Environmental Protection Agency (USEPA), and the Department of Agriculture (DOA). Ground-water
monitoring is also conducted by some counties and other special districts. The USGS National Water
Quality Assessment (NAWQA) Program studies, Safe Drinking Water Act monitoring requirements,
pesticide studies conducted by the DOA, or State and special district studies have stimulated some
localized ground water monitoring.
Other Federal agencies with monitoring programs include the National Park Service, National Oceanic
and Atmospheric Administration, Department of Defense/Corp of Engineers, Bureau of Indian Affairs,
Bureau of Land Management, Office of Surface Mining, Bureau of Reclamation, U.S. Forest Service,
and the Department of Energy. Their monitoring is localized and limited. Though efforts are
increasing, data are currently limited to selected aquifers scattered across the Region.
The USGS National Water Quality Assessment (NA WQA) Program
Despite the lack of comprehensive Region-wide data, there are a number of aquifer and watershed-
based water-quality monitoring activities. The USGS's National Water Quality Assessment
(NAWQA) Program is developing comprehensive and consistent trend data for ground and surface
waters in selected aquifers and watersheds across the United States. The program builds partnerships
with Federal, State and local agencies to collect and assess the necessary data.
To date, the NAWQA Program has completed assessments on:
the South Platte River Watershed in Colorado;
* the Red River of the North Watershed in North Dakota and Minnesota;
• the Upper Snake River Watershed in Idaho and Wyoming;
53
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the Rio Grande River Watershed in Colorado and New Mexico; and
• the Upper Colorado River Watershed in Colorado and Utah
NAWQA assessments in the High Plains (Ground Water Study in Colorado, South Dakota, Wyoming),
Yellowstone River Watershed in Wyoming and Montana, the Great Salt Lake Watershed in Utah, and
the Northern Rockies Intermontane Basins in Montana and Idaho will produce more information on
ground-water and surface-water quality in the next several years. The USGS also compiles extensive
atlas information on the location, geology, geography and hydrologic characteristics of the major
aquifers across the U.S. and conducts some monitoring and studies in each of the Region's States. See
Appendix C for a list of USGS NAWQA study websites/links.
State Ground-Water Quality Monitoring
Many State ground-water protection programs generate water-quality data. The nature and extent of
these programs vary across States, and some, such as South Dakota's monitoring network, are
developing into comprehensive State-wide efforts. Existing state ground-water quality data and
program efforts are summarized every two years in Water Quality Assessment Reports to Congress,
referenced in section III.B of this report. See section IV.B for more information on State ground-water
classification, permits, and standards. Appendix B contains State ground-water program contacts and
websites.
Colorado
Since 1992, all of the major shallow aquifers in agricultural areas of Colorado have been assessed for
water quality. This work has been performed in response to Colorado Senate Bill 126 and Clean Water
Act 305(b) report requirements. The Water Quality Control Division of the Colorado Department of
Public Health and Environment is responsible for collecting ground-water samples from the various
shallow aquifers and evaluating the water quality results for impacts from agricultural chemicals. To
date the aquifers assessed include the South Platte River alluvium, the San Luis Valley alluvium, the
Lower Arkansas River alluvium, the Ogalala Aquifer, and the Western Slope (i.e., Green, Colorado,
and San Juan rivers) alluvium.
Montana
The Montana Groundwater Assessment Program (see Section IV.B for more information) includes a
statewide network of monitoring wells in which static water levels are measured quarterly; about 70 of
the wells are equipped with continuous water-level recorders. The State collects about 200 ground-
water quality samples statewide on an annual basis. This data, as well as that from other hydrogeologic
studies, are stored in the Bureau of Mines and Geology's Groundwater Information Center (GWIC).
Data from GWIC are easily transferred to GIS for display and analysis and can be exported
electronically or on paper.
54
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The Montana Department of Agriculture performs long-term ground-water monitoring for the presence
of agricultural chemicals. The current statewide monitoring network is limited to eight monitoring
wells in selected areas based on lithological and hydrological characteristics and agricultural systems
typically found in the state. Additional wells will be installed as funding permits.
North Dakota
Ambient ground-water quality monitoring is conducted by several State agencies, with most conducted
by the State Water Commission (SWC) and the State Health Department. The monitoring programs
have been developed to assess ground-water quality and/or quantity in the major aquifer systems
located throughout the state. Analytes include inorganics, organics, and selected agricultural chemical
compounds.
In 1992, the Division of Water Quality initiated an Ambient Ground Water Monitoring Program to
determine the occurrence of 50 selected agricultural pesticides in the 50 most vulnerable aquifer
systems in the State within a 5-year period. Approximately 1200 wells have been monitored. Tables
IV-15 toIV-19 of the North Dakota Year 2000 305(b) report summarize synthetic organic chemical
and nitrate detections in selected aquifer systems. The Ambient Ground Water Quality Database
maintains records for approximately 1,393 different wells, from which 1,969 samples have been
collected to date.
South Dakota
The DENR (Department of Environment and Natural Resources) implemented the Statewide Ground
Water Quality Monitoring Network in 1994 and completed well installation in 1998. It is a permanent
network of 145 monitoring wells at 80 sites in 24 sensitive shallow aquifers in South Dakota. The
network goals are to assess (a) the present ground water quality, (b) the impact of agricultural
chemicals on ground water, and (c) long-term trends in water quality in sensitive aquifers. Parameters
being analyzed are major ions, trace elements, radionuchides, volatile organics, and pesticides. In
1999, all 145 wells were sampled.
Utah
The Department of Environmental Quality monitoring program was recently expanded to monitor
ground water in parts of the state where there are concerns about water quality. Current projects
include Cedar Valley/Iron County baseline ground-water quality study, Millard County baseline water
quality study, Mammoth Creek septic tank impact study, and the East Canyon Creek ground-
water/surface-water interface study.
The Utah Department of Agriculture has collected almost 2000 ground-water samples from private
domestic wells in rural areas of the state over the past several years. The samples are tested for general
inorganic, bacterial, and selected pesticide analyses, and the results are provided to the well owners.
The Department is emphasizing agricultural areas where ground-water sampling has not been done in
the past to the same extent as other areas of the state. The Department of Agriculture is also
determining the vulnerability of major ground-water basins to contamination. The results will direct
future ground-water monitoring activities.
55
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Wyoming
There are two significant statewide ground-water monitoring efforts in Wyoming: (1) ground-water
monitoring associated with implementation of the State Management Plan for Pesticides in Ground
Water (SMPPGW), and (2) planning for future ground-water monitoring under the Statewide Ambient
Ground-Water Monitoring Program.
Aquifers that are vulnerable to contamination by agricultural contaminants are monitored under the
SMPPGW. Using the ground-water sensitivity and vulnerability maps from the Wyoming Ground-
Water Vulnerability Mapping Project, a technical committee, comprised of members of the WDEQ,
USGS and WDA, determines the sampling locations for vulnerable aquifers within each county in
Wyoming. Ground-water wells at these locations are sampled in the spring and fall each year in three
or four counties and analyzed for selected agricultural chemicals. Sampling by the USGS has occurred
in 14 Wyoming counties (out of a total of 23 counties). Once all Wyoming counties have been selected
for sampling a decision will be made as to if and when sampling will be done again under this
program.
In 1998, the WDEQ began to develop a program to routinely monitor ambient ground-water conditions
in selected, high priority aquifers or portions of aquifers. A statewide map which depicts four classes
of Ground-Water Protection Priority Areas was completed in 2000. These Areas were delineated based
on aquifer sensitivity, primary use of water, and land use (vulnerability). The Statewide Ground-Water
Sensitivity Maps, produced as part of the Wyoming Ground-Water Vulnerability Mapping Project,
were used as the base map for delineating and depicting the Ground-Water Protection Priority Areas.
WDEQ is determining 1) how many wells to sample in each Priority Area, 2) which analytes will be
included, 3) what the cost will be, and 4) who will conduct the sampling. WDEQ will implement the
monitoring program and distribute the monitoring program data to the public and to all interested
government and quasi-government agencies.
Compliance Monitoring
Compliance monitoring associated with regulatory requirements also generates an extensive amount of
site-specific monitoring data for ground-water contamination sites, primarily from Superfund, RCRA,
Underground Storage Tank, DOE, and DOD sites; ground-water data are also collected as part of
permitting requirements for mining and waste disposal. The data from these studies are not generally
placed in a common database and often are not electronically available. Therefore, it has been difficult
to use these data for more than individual site-specific purposes. To acquire such data would require
contacting the regulatory or oversight agency directly.
Drinking Water Monitoring
The monitoring requirements of the Safe Drinking Water Act (SDWA) mandate that public water
systems monitor the quality of their water after treatment. Therefore, drinking water systems data is
56
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an indication of the quality of treated water rather than the quality of the raw source waters. However,
many small/rural systems only chlorinate their drinking water; in those cases the data do represent raw
source water.
Additionally, even though there are Standards for over 80 drinking water contaminants, plus monitoring
requirements for dozens more, the SDWA allows States to grant "monitoring waivers" to public water
systems. These waivers are based on either "non-use" of a contaminant or "low-vulnerability" of the
water system's source. Water systems are allowed to forego monitoring for certain periods of time.
Waivers are relatively new and are not granted widely. Variations in the stringency of monitoring
waiver programs from state to state have led to differences in the amount of monitoring that has
actually been required and performed by public water systems.
Data and Information
There are three primary electronic databases used to store ground-water data in Region 8. They are:
EPA's STORET database, EPA's SDWIS (Safe Drinking Water Information System), and the USGS
National Water Information System (NWIS) Database. Many of the State agencies, such as the
Colorado Department of Public Health and Environment, have developed their own databases where
they store ground water quality data.
Prior to 1999, the USGS placed its NWIS database onto STORET. Since 1999, databases have been
incompatible and cannot be merged. NWIS is the most complete database for ground-water
information in Region 8. Its data are available through the USGS web site at.water.usgs.gov/nwis.
EPA uses STORET for surface-water data, ground-water data, and air, sediment, soil, and biological
information. In theory, if the EPA provides funding for ground-water data collection to another federal
agency, state agency, or other group, then the data must be entered into STORET; in practice, that does
not always occur. EPA is asking that volunteer monitoring data and tribal data be entered on
STORET. STORET does not include any public water supply data or RCRA ground-water monitoring
data. Some CERCLA site data are being entered into STORET, but this is on a site-by-site basis and is
not mandatory. The EPA Region 8 contact for STORET is Marty McComb at
inccomb.martingtepa.gov (Phone 303-312-6963, EPR Program Support).
The EPA SDWIS database stores data about public drinking water supplies from ground-water and
surface-water sources. It includes locations of public water systems and indicates whether or not the
system is in compliance with drinking water standards. SDWIS does not include analytical results
(concentration levels) unless there was a violation of a drinking water standard. The public does not
currently have access to the SDWIS database due to security concerns, but the public may access
specific information through a Freedom of Information Act request
fwww.epa.gov/region08/about/foia/foia.htmlV EPA is currently in the process of deciding what
SDWIS data will be available to the public versus what will be restricted.
57
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The 1996 Amendments to the Safe Drinking Water Act require EPA to develop a new "national
drinking water contaminant occurrence database." This database will contain information on both
regulated and unregulated contaminants (physical, chemical, microbial and radiological) found at a
"quantifiable level," not just those in violation of EPA standards. This information will help EPA
determine for which new contaminants it should develop standards. It will also provide a more
complete picture of drinking water quality in the Region. For more information on this database, see
www. ena.gov/ncod.
58
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IV. GROUND-WATER PROTECTION AND MANAGEMENT
PROGRAMS
IV.A. EPA GROUND-WATER PROTECTION PROGRAMS AND
AUTHORITIES
In 1984 U.S. EPA issued its "Ground-Water Protection Strategy", which combined its statutory
authorities and a preventative approach to groundwater management. State and local
ground-water protection programs were developed and implemented out of the initiatives and
legislation stimulated by the strategy.
Many EPA programs are implemented at the state level through delegation of the program to state
agencies. Others are implemented directly by the EPA Regional office. Table 10 below summarizes
federal authorities to assess, protect and remediate ground-water quality, and state or local activities
associated with those authorities. Program delegation status is included under the "State activities"
heading in Table 10.
Even with these authorities, the EPA's ability to prevent contamination of ground water or address
existing contamination is limited. Some of the limitations exist because EPA does not have authority
to address issues that are not covered by current laws. Other limitations stem from the fragmented
nature of the authorities themselves. For example, EPA's authorities to address ground-water quality
issues lie under five different statutes which are implemented and/or overseen by seven different EPA
Programs. Workloads specific to each legal authority, and the complexity of the legal landscape makes
effective coordination among ground-water programs difficult. Inadequate staff and funding combined
with a relatively weak emphasis on ground water further hamper efforts to coordinate programs.
59
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TABLE 10
EPA PROGRAMS AND AUTHORITIES TO PROTECT AND REMEDIATE
GROUND WATER
FKDKRAL PROGRAM
DESCRIPTION
STATE ACTIVITIES
Sole Source
Aquifer
Safe Drinking Water Act Section
1424(e)
authorized 1974, revised 1986
Orientation: Pollution Prevention
Ongoing
Allows individuals and organi-
zations to petition the EPA to
designate aquifers or portions of
an aquifer as the "sole or princi-
pal source" of drinking water for
an area. If so designated, all
federally assisted projects planned
for the area are subject to review
by EPA to determine their
potential for contaminating the
aquifer. There are approxi-
mately 70 SSAs across the U.S.
States do not administer the SSA
program,
SSAs in Region 8 by State
Montana: Missoula Valley
Aquifer
Utah: Western Uinta Arch
Paleozoic Aquifer System at
Oakley and the Castle Valley
Aquifer System near Castle
Valley
Wyoming: Elk Mountain Aquifer
Wellhead Protection
Program (WHP)
Safe Drinking Water Act Section
1428
authorized 1986, revised 1996
Orientation: Pollution Prevention
Ongoing
The goal of this program is to
prevent contamination of ground
water used for community water
supplies.
Steps: *forrn a local team;
* delineate the part of the aquifer
that provides water to a public
water supply well or wellfield
(wellhead protection area
(WHPA));
* identify and characterize
potential sources of contaminants
within the WHPA;
* develop and implement a
management plan for the WHPA
* plan for possible spills
(contingency plans)
* do WHP for new wells
States were required to prepare
WHP Programs for EPA
approval. All of the states in
Region 8 have approved WHP
Programs.
Local governments, communities,
or public water systems develop
and implement WHP plans,
covering all six steps, for their
individual public water systems in
accordance with the state's WHP
Program.
Local participation is voluntary in
all Region 8 states except Utah.
Participation is optional, but
encouraged, for tribes. As
resources allow, the Region
provides technical assistance and
financial support.
60
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TABLE 10
EPA PROGRAMS AND AUTHORITIES TO PROTECT AND REMEDIATE
GROUND WATER
FEDERAL PROGRAM
DESCRIPTION
STATE ACTIVITIES
Source Water Assessment
Program
Safe Drinking Water Act Section
1453
authorized 1996
Initial completion expected 2003
(42 months after state program
approval) Assessment updates
are desirable, but not required.
Protection is desired but not
required.
Orientation: Pollution Prevention
The goal of this program is to
provide information meant to
form a basis for local protection
activities, including wellhead
protection, to all public water
systems and their customers.
Source Water Assessments are to
be completed for all public water
systems, including these steps:
* Delineation of a source water
protection area and/or wellhead
protection area
* Inventory of potential sources
of contamination in these areas
* Susceptibility determination for
each public water supply source to
contamination
An assessment report is sent to
each public water system and
available to the public.
SWAPs are not intended to
replace existing programs, but to
focus federal, state and local
attention on protecting the sources
of safe drinking water.
State and local governments were
very involved in helping EPA
develop the SWAP strategy.
States with primary enforcement
authority for the Public Water
Supply Supervision Program are
required to establish and complete
Source Water Assessment
Programs. Wyoming does not
have primary enforcement
authority and has a voluntary
SWAP.
SWAP is optional for Tribes. The
Region provides technical support
for source water assessments and
funding for technical service
providers.
All six Region 8 states have
approved SWAPs.
Protection of sources of drinking
water is expected to take place on
the local level using local
authorities and existing state and
federal programs, including
wellhead protection programs,
state ground-water protection
strategies, sole source aquifer
designations, and other
established programs, such as
those under the CWA or RCRA.
Ground Water Rule
Safe Drinking Water Act Section
1412(b)(8)
authorized 1996
The final rule is expected to be
published in the Federal Register
in 2004.
Orientation: Public Health
Protection
Sets criteria to determine whether
public water systems using ground
water must disinfect their water
for additional protection against
bacteria and viruses.
States with primary enforcement
authority are expected to set
criteria. May coordinate with
Source Water Assessments or
other state ground-water assess-
ment and protection efforts.
EPA Region 8 will directly
implement in Wyoming and on
Tribal Lands.
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TABLE 10
EPA PROGRAMS AND AUTHORITIES TO PROTECT AND REMEDIATE
GROUND WATER
FEDERAL PROGRAM
DESCRIPTION
STATE ACTIVITIES
Underground Injection
Control Program
Safe Drinking Water Act
Sections 1421 through 1426
authorized 1974
amended 1981, 1984
Orientation: Pollution Prevention
Ongoing
Through permits, EPA's
Underground Injection Control
Program protects all underground
sources of drinking water from
contamination by requiring that
all wells injecting liquids into the
ground meet specific construction
and operation standards.
There are five classes of injection
wells.
Class I: Deep injection wells for
hazardous and nonhazardous
waste.
Class II: Brine injection wells
related to oil and gas production.
Class III: Solution mining wells
injecting water, steam, or other
fluids to recover minerals.
Class IV: Shallow wells injecting
hazardous waste. BANNED
Class V: All other injection
wells.
A 1999 rule specifically regulates
cesspools (banned) and septic
systems serving more than 20
people and regulates motor
vehicle waste disposal wells.
Other Class V wells may need to
be permitted by rule or
individually.
This program may be delegated
to states whose rules and
regulations meet the requirements
for the part(s) of the program
delegated.
1422 delegations in Region 8
include only UIC well Classes I,
III, IV, and V. These programs
have been delegated to North
Dakota, Utah, and Wyoming.
Section 1425 delegations are
special to UIC Class II wells (oil
& gas-related). This program has
been delegated to all six Region 8
States.
EPA Region 8 implements all
UIC programs on Tribal Lands.
Class IV well closure is up to the
implementing authority, with
EPA over-file enforcement
authority for nonperformance by
the delegated agency.
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TABLE 10
EPA PROGRAMS AND AUTHORITIES TO PROTECT AND REMEDIATE
GROUND WATER
FEDERAL PROGRAM
DESCRIPTION
STATE ACTIVITIES
Hazardous Waste
Programs
Resource Conservation and
Recovery Act Subtitle C -
general
authorized: 1976
amended: 1984,1992,1996
RCRA enhanced the 1965 Solid
Waste Disposal Act
Orientation: Pollution
Prevention and Remediation
Ongoing
RCRA Subtitle C is a
comprehensive program to
ensure that hazardous waste is
managed safely from when it is
generated, through storage,
transportation, or treatment, and
during and after disposal. EPA
and/or states issue permits,
inspect facilities, and require
corrective action to address
contamination that may affect
ground water or other
environmental media, or human
health.
State hazardous waste programs
may be authorized to operate in
lieu of federal standards. The
state program and regulations
must meet or exceed federal
standards. EPA retains over-file
enforcement authority for
nonperformance by the
delegated agency.
All six Region 8 states are
authorized for at least the base
program under RCRA Subtitle
C.
The Region directly implements
RCRA Subtitle C on Tribal
Lands.
Corrective Action
Program
Resource Conservation and
Recovery Act Subtitle C,
Hazardous and Solid Waste
Amendments
authorized: 1976, amended 1984
Orientation: Pollution
Prevention and Remediation
Ongoing
The RCRA Corrective Action
program is specifically focused
on active facilities where human
exposure and ground-water
contamination risks exist as a
result of poor waste
management and handling
practices. EPA and/or states
administer the clean up and
control of these hazardous waste
sites.
States may be approved for
implementation in lieu of the
federal program. All six R8
states are authorized to
implement the Hazardous Waste
Programs.
The Region directly implements
this program on Tribal Lands.
There are 57 facilities in the
Corrective Action category in
Region 8.
63
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TABLE 10
EPA PROGRAMS AND AUTHORITIES TO PROTECT AND REMEDIATE
GROUND WATER
FEDERAL PROGRAM
DESCRIPTION
'STATE ACTIVITIES
Solid Waste
Management Programs
Resource Conservation and
Recovery Act Subtitle D -
general
authorized: 1976
amended: 1984,1992, 1996
RCRA enhanced the 1965 Solid
Waste Disposal Act
Orientation: Pollution
Prevention
Ongoing
RCRA Subtitle D addresses the
management of solid waste,
municipal solid waste, and
hazardous waste exempt from
Subtitle C, such as household
hazardous waste. The goal of
this program is to manage solid
waste in an environmentally
sound manner and to maximize
reuse. EPA's primary role is to
develop national goals, provide
leadership and technical
assistance, and develop guidance
and educational materials.
State and local governments
implement RCRA subtitle D.
Municipal Solid Waste
Land/Ill Criteria
Resource Conservation and
Recovery Act Subtitle D
Orientation: Pollution
Prevention
Ongoing
Under RCRA Subtitle D, EPA
has set technical requirements for
Municipal Solid Waste Landfills
to ensure that human health and
the environment, including
vulnerable ground water, are
protected.
EPA provides funding and
technical assistance for the
implementation of these
regulations in Indian Country.
States and local governments
are the primary regulatory
entities for RCRA Subtitle D
provisions, including
regulations. All six R8 states
are authorized to implement the
Municipal Solid Waste
Program.
While EPA does not directly
implement a RCRA Subtitle D
permit program for municipal
solid waste landfills in Indian
Country, facilities located in
Indian Country must comply
with the regulations in 40 CFR
part 258.
64
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TABLE 10
EPA PROGRAMS AND AUTHORITIES TO PROTECT AND REMEDIATE
GROUND WATER
•FtiDERAi. I'ROGR&M
Underground Storage Tanks
Program
Resource Conservation and
Recovery Act Subtitle I
Authorized 1984
Orientation: Pollution Prevention
and Remediation
Ongoing
Cotnpreh ensive
Environmental Response
Compensation and Liability
Act (CERCLA orSuperfund)
General authorized: 1980
funding extended: 1984 (5-year
funding),
amended: 1986 (Superfund
Amendments and
Reauthorization Act)
Orientation: Remediation
Ongoing
The UST program is a compre-
hensive regulatory program for
underground storage tanks that
contain petroleum or certain
hazardous substances. These
regulations are designed to ensure
that operators of new tanks and tanks
already in the ground pre- vent.
detect, and clean up the releases.
Regulations include minimum
standards for new tanks and technical
requirements to upgrade, replace or
close existing tanks to meet leak
detection and prevention standards
by December 22, 1998. Operators
are also required to demonstrate that
they are financially capable of
cleaning up releases and
compensating third parties for
resulting damages.
The goal of this program is to
clean up abandoned waste
disposal sites and ground water
contaminated with hazardous
substances. The program also
provides for federal emergency
response where immediate action
is needed to limit or prevent
further endangering human health
or the environment. EPA
administers the clean up of these
hazardous waste sites under the
authority and funding of
CERCLA. Accidental spills and
poor waste management practices
have resulted in a number of
CERCLA sites in Region 8. At
least 20 of the 52 active sites in
Region have ground-water
contamination issues.
State programs in Montana, North
Dakota, South Dakota, and Utah
are approved for implementation
in lieu of the federal program. In
addition, Colorado and Wyoming
are implementing their state
programs under Cooperative
Agreements with EPA.
The Region directly implements
the program in Indian Country.
States are key players in
remediation of contaminated
sites, including operations and
maintenance of remedies. The
state may be the entity with
greatest enforcement authority
to require implementation of
institutional controls or other
remedies based on state statute
or regulation.
CERCLA actions are usually
closely coordinated with
appropriate state agencies, as
needed.
States are Natural Resources
Trustees under CERCLA,
requiring that EPA keep them
informed of actions within their
boundaries.
65
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TABLE 10
EPA PROGRAMS AND AUTHORITIES TO PROTECT AND REMEDIATE
GROUND WATER
FEDERAL PROGRAM
DESCRIPTION
STATE ACTIVITIES
Clean Water Act
1977 amendment to the 1972
Water Pollution Control Act.
Orientation: Pollution Prevention
and Remediation
Ongoing
Provides authority for federal
regulation of pollutant discharges
to waters of the US (surface
water). Goals of the Act are to
eliminate pollutant discharges and
to achieve water quality that is
fishable and swimmable in all
waters of the US.
While not regulated under the
CWA, ground-water quality can
have a profound effect on surface-
water quality. This is addressed
through several programs under
the CWA, but not by direct
permits.
States may have permitting
programs for waste water
discharges that target impacts to
ground water. All 6 states in
Region 8 have some kind of
ground water permitting program
(see section IV.3).
Non-Point Source
Program
Clean Water Act Section 319
authorized: 1987
Orientation: Pollution Prevention
and Remediation
Ongoing
The Non-Point Source Program
provides funding to states, tribes,
and others for effective
management of diffuse sources of
contaminants to reduce or prevent
pollution of surface waters.
Solutions must consider impacts
to ground waters. Funding may
be used to carry out ground-water
quality protection activities,
including assessments, as part of a
comprehensive non-point source
pollution control program.
States may target 319 funding to
ground-water projects.
Tribes need to achieve "treatment
as a state status" pursuant to
Section 518 of the Clean Water
Act to receive 319 funding.
66
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TABLE 10
EPA PROGRAMS AND AUTHORITIES TO PROTECT AND REMEDIATE
GROUND WATER
FEDERAL PROGRAM
INSCRIPTION
STATE-ACTIVITIES
Section 106
Clean Water Act
Authorized: 1985
Orientation: Assessment and
Pollution Prevention
Ongoing
Section 106 provides funding for
state water-quality monitoring
activities, including a
recommended minimum 15% for
ground-water quality programs,
including the development of
state ground-water strategies.
All six R8 states traditionally
devote more than the 15%
minimum to ground-water quality
programs, including ambient
ground-water quality monitoring
programs and Wellhead
Protection programs. All are
under the state PPGs.
Tribes may use CWA special
studies funds to assess and
monitor ground water in Indian
Country.
Total Maximum Daily
Loads
Clean Water Act Section 303 (d)
Authorized: 1972, Regulations
issued: 1985, 1992
Orientation: Remediation
Ongoing
Requires the quantification of
specific pollutants impairing the
quality of a surface-water body.
Loading from ground water
should be considered in the
TMDL, but is not required to be
addressed. EPA is required to
perform TMDLs if the state has
not done so:
States carry out TMDLs as part of
their water-quality programs.
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TABLE 10
EPA PROGRAMS AND AUTHORITIES TO PROTECT AND REMEDIATE
GROUND WATER
FEDERAL PROGRAM
Federal Insecticide,
Fungicide, & Rodenticide
Act
Authorized; 1978, Amended:
1988
Orientation: Pollution Prevention
Ongoing
DESCRIPTION
FIFRA provides federal control
of pesticide distribution, sale, and
use. All pesticides used in the
United States must be registered
by EPA. Registration and proper
labeling ensure that pesticides
will not cause unreasonable harm
to the environment, including
ground water.
EPA must classify a product or
some uses of a product as
"restricted use" if they may cause
unreasonable adverse effects to
human health or the environment,
including leaching into ground
water. Restricted-use pesticides
are limited to use by certified
pesticide applicators.
STATE ACTIVITIES
To be legally used in a state, a
pesticide must also be registered
there. States can be more
restrictive than EPA based on
local conditions. States are
primarily responsible for
enforcing pesticide regulations.
In addition, six Region 8 tribes
also have their own pesticide
programs.
States/Tribes may choose to
certify pesticide applicators under
FIFRA Section ll(a)(2). All six
R8 states have such programs for
commercial applicators.
In states/tribes that do not develop
their own plan for applicator
certification, EPA (or in the case
of tribes, the state within which
the tribe is located) administers
an applicator certification
program in accordance with
FIFRA Section ll(a)(2).
All six R8 states have generic
State Management Plans for
pesticides which include
frameworks for real-time ground-
water monitoring.
68
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IV.B. STATE GROUND-WATER PROTECTION PROGRAMS
All of the Region 8 states have developed ground-water protection efforts that exceed Federal
requirements. The primary elements within all Region 8 ground water protection programs include
ground-water classification, in-situ ground-water quality standards, and ground-water discharge
permitting. The elements are described in general below. Table 11 contains the relevant statute or
rule and web page to access detailed information on each program for each state. See Appendix B for
additional state contacts and web sites.
Ground-Water Classification
AH Region 8 states have
classified some ground
water resources, established
itt~situ ground-water qualify
Standards, and set up
ground-water discharge
permitting.
The purpose of the classification scheme determines how
ground water is classified. Schemes are typically based on
the current and/or potential beneficial uses of the resource
(e.g., drinking water use, agricultural use, industrial use)
and the classified areas differ in terms of boundary criteria
(e.g., political, aquifer or aquifer zone, watershed,
permitted discharge facility). Ambient ground-water
quality (such as TDS or specific conductance) is
commonly used to define the various classes of ground
water.
Most state ground water classification schemes are based on TDS. For example, in North Dakota and
South Dakota ground water is classified as either drinking water use if the TDS level is less than
10,000 ppm, or no specific beneficial uses if the TDS level exceeds 10,000 ppm. The classifications
are used to establish in-situ water-quality standards (see below) for implementing ground-water
protection programs, permitting discharges to ground water, and setting cleanup goals at contaminated
sites. In North Dakota, a second classification system based on aquifer sensitivity (using the EPA
DRASTIC model, described in the box below) is also used to prioritize ground-water monitoring to
track the occurrence of agricultural chemicals and to help determine state activities in the UIC Class V
program.
The DRASTIC model is a ground water sensitivity assessment
tool that incorporates the following parameters! I) = depth to
water; R - recharge; A - aquifer matrix; S = soil type; T =
topography; 1 ~ impact of the vadose zone; C - hydraulic
conductivity.
69
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In Colorado, a public hearing process in front of the State Water Quality Control Commission is
required to classify specific ground water to set ground-water quality standards for protection and
regulatory purposes. The classification scheme includes: domestic use-quality; agricultural
use-quality; surface water quality protection; potentially usable quality; and limited use and quality.
70
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TABLE 11
OVERVIEW OF STATE GROUND-WATER PROTECTION PROGRAM ELEMENTS
Classification
• System
In-Situ
Ground-Water
Quality
Standards
Discharge
Permits
..,
Colorado
5CCR(Codeof
Colorado
Regulations)
1002-41.4
www.cdphe.state.
co. us/op/reas/ 1 00
241.pdf
5 OCR 1002-41.5
www.cdphe.state.
co.us/op/rees/100
241.pdf
5 OCR 1002-61
www.c dphc .state.
co.us/op/regs/JOO
261.pdf
Montana
ARM 17
(Administrative
Rules of Montana,
Title 17) Chapter
30, Subchapter 10
www.deq .state.mt
.us/dir/leeal/Chapt
ers/CH30-10.pdf
MTDEQ Circular
WQB-7
www.deq.state.mt
.us/wqinfo/CircuS
ars7WOB-7.pdf
ARM 17, Chapter
30, Subchapter 10
www.deq. state.mt
.us/dir/Ieeal/Chapt
ers/CH30-10.pdf
North Dakota
Chapter 33-3 6-
02,1-10
www .health, state .
hd.us/ndhd/enviro
n/wq
Chapter 33-16-
02.1-10
www .health. state.
nd.us/ndhd/enviro
n/wq
Chapter 33-16-
02,1-11
www. health, state.
nd.us/ndhd/enviro
n/wg_
South Dakota
ARSD
74:54:01:03
www. le sis. state, s
d.us/niles/index.cf
m
ARSD
74:54:01:04
www.legis. state, s
d.us/rules/index.cf
m
ARSD 74:54:02
www.legis. state, s
d .us/rules/index.c f
m
Utah
UACR317-6-3
www.deq .state, ut.
us/publicat/code/r
3 17/r3 17-006.htm
UACR3 17-6-2
wv/w.deq.state.ut.
us/publicat/code/r
317/r317-006.htm
UACR3 17-6^6
www.deq.statc.ut.
us/publ icat/codc/r
3 17/r3 17-006.htm
Wyoming
WDEQ Chapter
8
http://deq. state. w
y^us
WDEQ Chapter
8
httD://dea.state.w
Y^us
WDEQ Chapter
9
http://deq.state.w
yjis
71
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The State of Utah has established four ground-water classes with subclasses defined within
Class I.
UTAH GROUND-WATER CLASSIFICATION
• Class 1A or pristine ground water has a total dissolved solids level of less than
500 milligrams per liter (mg/l) and no contaminant concentrations that exceed
State ground-water quality standards.
• Class IB or irreplaceable ground water is a source of water for a community
public drinking water system for which no reliable supply of comparable quality
and quantity is available because of economic or institutional constraints.
• Class 1C or ecologically important ground water is a source of ground-water
discharge important to the continued existence of wildlife habitat,
• Class 11 or drinking water quality ground water has a total dissolved solids level
greater than 500 mg/l and less than 3000 mg/I and no contaminant concentrations
that exceed state ground-water quality standards.
• Class HI or limited use ground water has a total dissolved solids level greater
than 3000 mg/l and less than 10,000 mg/l and/or one or more contaminants that
exceed state ground-water quality standards.
• Class IV or saline ground water has a total dissolved solids level greater than
Application of Water-Quality Standards to Ground Water
Water-quality standards include maximum (or, for a few parameters, minimum) levels allowed
by State regulation for potential contaminants. Standards are determined based on state ground-
water classification systems, ground-water clean-up goals and ground-water discharge permit
requirements. Table 11 gives web locations for standards in each state. Numeric standards set
by the Region 8 stales include the Maximum Contaminant Levels (MCLs) and Secondary*
Maximum Contaminant Levels (SMCLs) for public drinking water supplies as established by the
Safe Drinking Water Act regulations. Additionally, in Colorado, some numeric standards are
set based on Ambient Water Quality Criteria (existing quality in the aquifer), recommended
agricultural use values, and/or human-health risk assessment levels. In South Dakota, the
standards for some potential toxic pollutants, primarily pesticides, are set at laboratory detection
limits (i.e., nondetectable levels),
Region 8 states have applied existing water-quality standards to ground water using state statutes
or rules administered under state ground-water protection programs. Some of the states have
72
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established preventative action limits as an early warning of the presence of pollution before
beneficial uses are adversely affected, and to achieve more stringent protection for higher quality
ground water. For example, in Utah preventative levels are set in the ground-water discharge
permits (see section below on permits). The levels are set at 10 to 50 percent of the standard; if
pollutant concentrations are detected that exceed the protection levels, then the source of the
problem must be corrected.
Montana's nondegradation rules apply to any activity resulting in a new or increased source
which may cause water-quality degradation due to carcinogens. Degradation is defined as "a
change in water quality that lowers the quality of high-quality waters for a parameter." The
State determines whether a proposed activity may cause degradation based on information
submitted by an applicant. Contaminants other than carcinogens are regulated under an anti-
degradation policy. The policy allows for an increase in concentration of a contaminant in
ground water, but not an exceedance of a standard.
Ground-Water Discharge Permits
In many states, facilities that discharge waste or pollutants directly or indirectly into ground
water (other than those regulated under UIC or NPDES) may be required to apply for a ground-
water discharge permit. The goal of this program is to allow economic development while
maintaining ground-water quality; in most cases, a limited zone of pollution is permitted and
quarterly compliance monitoring is instituted by the permittee. Ground-water quality standards
and/or protection levels are used to determine the discharge requirements.
Facilities required to apply for ground-water discharge permits are identified in the regulations.
For example, Colorado requires all facilities under certain standard industrial classifications
(SIC) to apply for permits and some of these facilities are covered under a general permit for
their SIC. In Utah, facilities that pose little or no threat to ground-water quality or that are
permitted by other State ground water protection programs (e.g., septic tanks, discharges from
permitted RCRA units) receive a permit by rule.
In South Dakota, a
discharge plan
includes three permits:
a ground-water quality
variance; a facility
construction permit;
and a discharge
permit.
Generally, a facility needing a permit would submit information
to the state that describes the extent and quality of the ground
water, the volume and composition of the discharge, how the
discharge will be controlled or treated to meet standards and/or
protection levels, and proposed inspection/monitoring plans to
ensure compliance with the terms of the permit In some States
(e.g., Utah), the permitting process requires a contingency plan
to bring the facility into compliance in the event of a significant
release of contaminants to ground water from the facility. In
South Dakota, a discharge plan includes three permits: a
ground-water quality variance; a facility construction permit; and a discharge permit from the
Ground Water Quality Program (GWQP).
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State Management Initiatives
In addition to federally mandated programs, the Region 8 states have characterized and protected
their ground-water resources with a wide variety of tools. Some case studies are given below to
highlight various approaches and share ideas that have worked.
/. Wyoming Ground Water Vulnerability Assessment
The Wyoming Ground Water Vulnerability Mapping Project was undertaken to: 1)
develop a mapping product that could assess the relative sensitivity of the state's shallow
ground-water resources to potential contamination, and 2) assess the vulnerability of
shallow ground-water resources to agricultural chemical application. This project is
innovative because current land use is considered via a two-step process. In the first •
step, the USEPA DRASTIC model is used to look at aquifer sensitivity as a function of
geohydrology, depth to water, slope, soils, and recharge. In the second step, sensitivity is
combined with data on pesticide use to determine relative ground-water vulnerability to
pesticide application across the state. The resulting vulnerability map shows portions of
aquifers that are vulnerable to pesticide application. Sensitivity and vulnerability maps
are available for each County in Wyoming at a scale of 1:100,000.
A product of the project is a dynamic, GIS-based tool to aid in planning, decision-
making, and public education related to the management of ground-water resources. The
tool could be used to plan for pesticide use and wellhead protection; management of
underground injection control facilities; local land-use planning; facilities management;
industrial siting; and education.
2. Wyoming Subdivision Rule
The WDEQ Water Quality Division's Subdivision Application Review Program was
designed and implemented in response to legislation enacted by the State Legislature in
1997. WDEQ reviews all applications for subdivisions submitted to county
commissioners to determine the adequacy and safety of proposed water supply and
wastewater systems. The purposes of the Subdivision Review Program are: 1) to ensure
that an adequate quantity of potable water is available to prospective lot buyers; 2) to
protect water supplies from sources of contamination due to improper design and
placement of wastewater systems; 3) to avoid costly water supply and wastewater system
modifications at the expense of the state; and 4) to fulfill the requirements of the 1997
statute. Individual counties determine what constitutes a subdivision application for
review. The WDEQ limits its review to water supply and wastewater system adequacy,
safety and compatibility with each other under site-specific conditions, A report from the
developer must be submitted to WDEQ with relevant engineering and/or geologic
information on the proposed water supply and wastewater systems. The Subdivision
74
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Review Program ensures that adequate consideration has been given to water supply and
wastewater issues prior to approval of a subdivision application at the county level.
3, Montana Ground-Water Assessment Plan
In 1991, Montana's legislature passed the Ground Water Assessment Act to address a
significant overall lack of information on the state's ground-water resources. The Act
established a comprehensive program to assess and monitor ground water for the long
term. This program consists of two parts: the Ground-Water Monitoring Program that
will establish a state-wide network of wells; and the Aquifer Characterization Study that
will identify and characterize important aquifers throughout the state. Both programs are
conducted by the Montana Bureau of Mines and Geology (MBMG); they receive
guidance and oversight from the Montana Ground Water Steering Committee, also
established by the Act.
A network of approximately 830 wells were established to monitor the principal surficial
and bedrock aquifers that are widely used for water supply. The water level in each well
is measured quarterly with about 10 percent of the wells having continuous water-level
monitoring. A long-term water-quality network has also been established. Data from the
program is entered into an electronic database and available through the MBMG.
For the Aquifer Characterization Study, the state was divided into 28 study units based
on county boundaries and general watersheds. MBMG will compile information on the
geology and ground-water resources of each study unit. Additional drilling and testing to
more accurately map the geology and determine the distribution and properties of
aquifers will be conducted. MBMG will also collect and analyze ground-water samples
to evaluate water quality and to better understand ground-water flow systems. The report
for each study area will discuss the availability of ground water, the potential for further
development, overall water quality, and the interaction between ground water and surface
water. Each report will also address issues related to ground-water management,
protection, and development. Currently, five study areas are in some stage of
characterization and three more have been prioritized for efforts over the next few years.
Various information/reports are available via the Internet and/or published documents.
4. South Dakota Statewide Ground-Water Quality Monitoring Network
South Dakota has designed and implemented a statewide monitoring network to assess
shallow ground-water quality. The goal of this monitoring effort is to systematically
examine the water quality and determine if any changes are occurring, including
impairment from nonpoint source pollution. This monitoring network is designed to
make the network and information as usable as possible for the greatest number of
people.
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This monitoring network will: 1) help formulate sensible and workable water
management and land use regulations for South Dakota, based on information from
South Dakota's aquifers, rather than information from some other part of the country;
and 2) allow early recognition of water-quality problems so that preventative measures
can be taken.
The aquifers are being monitored overmuch of South Dakota, with 146 water-quality
monitoring wells at 80 sites in 24 shallow aquifers. These aquifers are among the most
likely to be impacted by human activities because of their near-surface occurrence
combined with overlying land use. Each water-quality monitoring well in the network
contains dedicated sampling equipment, drastically reducing manpower needs and
ensuring representative samples. Ground-water samples from the network are being
analyzed for major ions, trace metals, radionuclides, volatile organic compounds, and
pesticides.
Results of this comprehensive monitoring have shown areas of elevated nitrate
concentrations in shallow aquifers. Also, the results of nearly 1,000 water sample
analyses have shown low-level pesticide detections. In the future the well samples will
analyzed for pesticide metabolites to ensure the ground water is safe for drinking.
5. Utah Mandatory Source Water Protection Program
The SDWA amendments of 1986 mandate the development of State Wellhead Protection
Programs, hi response, the State of Utah adopted rules for its EPA-approved Drinking
Water Source Protection (DWSP) Program. These rules set forth minimum requirements
public water .suppliers must implement to protect their ground-water sources of drinking
water. In 2000, the State adopted additional rules for its DWSP Program that also
required PWSs using surface-water sources and ground-water sources under the direct
influence of surface water to implement these requirements. The new rules were in
response to the 1996 amendments to the SDWA calling for development of an EPA-
approved Source Water Assessment and Protection Program.
The Utah DWSP Program differs from other Region 8 states' Well Head
Protection/Source Water Assessment and Protection programs because the Utah DWSP
Program is the only WHP/SWAP Program in Region 8 that requires implementation of
local protection measures by PWSs that serve people for long periods of time. The Utah
DWSP Program of 1993 required all PWSs using ground-water sources to develop
protection plans under a schedule enacted within the rules; these local protection plans
must include all of the elements provided .within EPA guidance on WHP Programs and
be approved by the DDW-UDEQ. The expanded rules of 2001 further require all PWSs
(that serve people water for long periods of time and that use surface-water sources and
ground water under the direct influence of surface water) to complete protection
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programs. These programs must control the three most significant potential contaminant
sources, with the goal of eliminating or reducing the risk of source water contamination.
6. Colorado Public Water System Organic Waiver Program
As authorized under the 1986 SDWA, the CDPHE has developed the Public Water
System Organic Waiver program which was approved by the EPA in 1999. Through this
program, the CDPHE can grant monitoring waivers for selected volatile and synthetic
organic contaminants to public water supply systems within Colorado. Waivers can be
granted based on lack of use of a particular organic contaminant or a determination that
the PWS well has a low susceptibility to contamination based on hydrogeologic criteria.
In order to implement the program the ground-water PWSs in Colorado were grouped
into three categories based on system size and a preliminary qualitative determination of
susceptibility. The groups to be reviewed included: 1) PWSs with wells more than 200
feet deep and protected spring sources, 2) PWSs with wells less than 200 feet deep and a
population served of greater than 175 people, and 3) PWSs with wells less than 200 feet
deep and a population served of less than 175 people.
Waiver applications from individual PWSs are initially reviewed to determine if a use
waiver is appropriate. A use waiver can be issued if the PWS can demonstrate that there
is no historical or current use of the organic contaminant within the area of influence of
the PWS well(s). A PWS can also request that CDPHE determine if a waiver can be
granted based on the more stringent susceptibility criteria. In order to be considered for a
susceptibility waiver a PWS must prove that its source water comes from a confined
aquifer.
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IV.C. TRIBAL GROUND-WATER PROTECTION PROGRAMS
Introduction
Governments and jurisdictions of 27 tribes and 26 reservations are found within EPA Region 8
boundaries. This section gives example success stories related to ground-water management at
two reservations. Find out more about the Region 8 Tribal Assistance Program at
www.epa.gov/region08/tribes or the EPA headquarters Indian Programs at
www.epa.gov/indian/programs.htm. The EPA Office of Ground Water and Drinking Water
Tribal Program information is at wvvw.epa.gov/safewater/tribal.html.
Tribal Ground-Water Management Initiatives
Spirit Lake Nation Reservation
The Spirit Lake Sioux Nation (in northeastern North Dakota) received several grants from EPA
under Clean Water Act Section 106 to examine the connection between the surface waters and
underlying aquifers on the Reservation. The goal of this study is to monitor and protect the
quality and/or quantity of their surface-water and ground-water resources. Another goal is to
build technical capacity within tribal government by involving tribal staff in scientific
procedures.
There are several issues related to protection of the Reservation aquifers, the Tokia and
Warwick. The Warwick aquifer is the primary drinking water source for rnore than 15,000
people and the City of Devils Lake. Protection of the two aquifers is affected by: current
agricultural activity in areas overlying the aquifers (irrigation); future development of ground
water for irrigation; and continued development of the aquifers for municipal uses. Integration
of all existing data and studies, and collection of water levels and water-quality data were
completed in Phase 1 Based on Phase 1 information, it was determined that a direct hydraulic
connection exists between the Warwick aquifer and overlying lakes and wetlands.
Phase II actions are:
•^ Collecting ground-water and surface-water level data and water-quality data in the
collection network;
/ Refining the GIS database to include all wells and test bores drilled during past 40 years;
/ Verifying locations of wells;
/ Building a GIS database of crop type distribution, pesticides/herbicide use, and irrigation
permits for ground-water withdrawal; and
y Determining optimal locations for additional monitoring wells, constructing 24 wells and
obtaining water-quality samples.
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Wind River Assessments
The Shoshone and Northern Arapaho Tribes on the Wind River Reservation in Wyoming
received Clean Water Act 106 funding from EPA to conduct a Water Resource Assessment and
Protection (WRAP) Program, described below. The Wind River Environmental Quality
Commission began Phase 1 of the Program in 1999.
Phase 1
The purpose of this Program is to assess the quality of the Reservation's valuable water
resources and protect them from sources of contamination. The project is modeled after the
EPA's Source Water Assessment and Protection Program. However, the Tribes' WRAP is not
limited in scope to public water supplies, but is directed at all surface- and ground-water
resources identified as critical to the Tribes. As more information is collected by the WRAP
Program, new areas of concern are identified. For example, the database of ground-water use,
water wells, and ground-water quality needs to be updated as new data are collected, and GIS
maps of potential sources of contamination such as 1STPDES discharge points and UST locations
need to be updated.
Phase 2
Phase 2 emphasizes protecting water quality in the shallow aquifer, which supplies water to
thousands of domestic wells on the Reservation. The aquifer is affected by individual septic
systems, and fertilizer, pesticide and herbicide applications, which need further investigation.
The Tribe needs to delineate the Reservation's primary aquifers and their recharge areas. Long-
term monitoring of water levels and water quality in the primary aquifers is needed to establish
baseline conditions for comparison to future conditions. This information will be invaluable to
the Tribes and EPA as more oil and gas development conies to the Reservation, including
exploration for coal bed methane.
Products from Phase 2 are:
/ An assessment of the effects of the rural home site and agricultural land use on the
quality of ground water in the shallow aquifers;
/ Assessment of radioactive trace element concentrations in ground water in the Crowheart
area;
^ A long-term baseline ground-water-quality monitoring program; and
/ A Tribal Wellhead Protection Program compatible with the State's Well Head Protection
Program.
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IV.D. CITY/COUNTY AND OTHER SUCCESS STORIES
Many local governments in EPA Region 8 have enacted programs to protect their ground-water
resources. Citizens have also led initiatives for ground water protection independently of
governments. Some examples are given below,
L Septic Tanks: Castle Valley
Castle Valley is in Grand County, Utah, in the east central part of the state. Castle Valley
is increasing popular as a site for vacation and retirement homes. Many new homes have
been built on 5-acre lots, each with its own well and septic system. In 1999 most of the
population of 274 in Castle Valley were living within the limits of the incorporated Town
of Castle Valley. The Utah School and Institutional Trust Lands is considering selling a
number of lots which may lead to a significant number of new homes in Castle Valley.
The increase in development and its potential impact on the quality of ground-water
resources has caused concern among local government officials who wish to preserve the
high quality of ground water in the valley-fill aquifer system.
In response to these concerns, the Utah Geological Survey (UGS) completed a study of
the valley-fill aquifer and has recommended locations for future public water supply
wells for the Town. This information was used by the Town and EPA to designate the
Castle Valley alluvial aquifer as a Sole Source Aquifer (see description in Table 9).
Using EPA funds, the UGS is completing an evaluation of the potential impacts of
additional septic tanks on the valley-fill aquifer. The authors will recommend a
minimum house lot size for future development to protect ground-water quality and
public health. The UGS is also using EPA funding to complete a petition to the, Utah
Water Quality Board to classify the ground water in the valley-fill aquifer for future
regulatory and protection actions. The Town of Castle Valley will be hiring a land-use
planning consultant who will use the results of these UGS efforts.
2. Feedlots: CAFO law in Colorado
Amendment 14 to the Colorado Revised Statutes was a citizen-based initiative approved
by the electorate on November 3, 1998. This statute required the Air Quality Control
Commission (AQCC) and the Water Quality Control Commission (WQCC) to develop
regulations for housed commercial swine feeding operations. All existing and new hog
operations subject to Amendment 14 were to be in compliance with the air and water
quality regulations by July 1, 1999.
The purpose of water quality Regulation No. 61, Section 13 is to ensure that the storage
and land application of waste from housed commercial swine feeding operations does not
contaminant Colorado's water resources. This rule requires an owner/operator to
develop a geohydrologic report for facilities where residual solids or swine feeding
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process wastewater are to be stored in lined earthen impoundments or land applied. The
report must define the local ground-water flow system and its potential connections to
surface waters. It must also include the locations of all existing wells/springs within one
mile of the proposed site, baseline ground-water quality data for the site, and the plans
for ground-water monitoring wells at the facility.
Mining: Zortman/Landusky Mines, Montana
The Zortman and Landusky mines are located in the south-central portion the Little
Rocky Mountains of north-central Montana; they are near the southern portion of the Ft.
Belknap Indian Reservation. Modern mining within this historic mining district occurred
from the late 1970s until the mid-1990s. The-mine companies used open-pit techniques
to extract gold and silver ore by conventional heap leaching methods. The last active
leach pad was constructed in 1991 and mining ceased in 1995. The Zortman and
Landusky operations disturbed about 385 acres and 814 acres of land, respectively.
Water-quality data collected over 20 years from ground-water monitoring wells indicate
that streams draining the mining district and ground waters within the syenite ore bodies
have been contaminated as a result of mining operations.
Potential sources of contamination include mine pits, spent ore heaps, waste rock dumps,
underground workings and process water ponds. Increased ground-water discharge from
the shear zone to Swift gulch has been observed since 1999. The extent to which ground
water within the syenite discharges to the flanking sedimentary rocks is unknown, but it
is thought to be minimal.
In January 1998 the owners of the mines filed for reorganization under Chapter 11 of the
federal Bankruptcy Code. Since 1998 the Montana Department of Environmental
Quality (MDEQ) has managed the site and taken the lead on remediating ground-water
and surface-water contamination and restoring disturbed lands, From 1998 to 2002, a
multi-agency Technical Workgroup made up of MDEQ, US Bureau of Land
Management, EPA, and the Ft. Belknap Tribes helped guide the restoration efforts at the
mines. A .Record of Decision (ROD) which specifies the interim and final restoration
activities has been signed.
The MDEQ has issued an Montana Pollution Discharge Elimination System permit
which includes the post-closure, long-term monitoring program. The monitoring
program includes contaminant source monitoring, early warning monitoring and
compliance monitoring for both surface and ground water. The environmental closure of
the Zortman /Landusky mines has focused on: 1) preventing further contamination of
ground water within the syenite ore; 2) preventing further contamination of surface water
within the affected drainages; 3) assuring that contaminated ground water or surface
water does not impact the Madison Limestone; and 4) completion of restoration activities
that are compatible with future Tribal use of the mined lands. The MDEQ is preparing to
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finish implementation of the preferred alternative and initiate the post-closure, long-term
water resources monitoring program.
4. Growth; Mountain Ground-Water Study, Jefferson County, CO
The Jefferson County Commissioners in 1998 initiated the Mountain Ground-Water
Study (MGWS). The study has been conducted by the USGS with guidance and
oversight from a Steering Committee comprised of representatives of Federal, State and
local governments as well as the public. Funding for the MGWS has been provided by
Jefferson County, the USGS, and EPA. The MGWS was completed in 2001.
The major goal of the MGWS is a detailed description of ground-water resources in the
Turkey Creek watershed in western Jefferson County. Extensive data and information
have been collected on the occurrence, flow, and quality of ground water in fractured
rock aquifers which underlie the forty-seven square mile watershed. The data have been
analyzed with a variety of characterization tools including outcrop mapping, water-
quality analyses, collection and analyses of evapotranspiration data, hydrograph analyses,
and ground-water modeling (Precipitation and Runoff Modeling System - PRMS). A
sound conceptual understanding of the aquifers/ground-water flow systems within the
watershed will result from these analyses.
The growth in western Jefferson County and the increased demand for ground water for
domestic supply necessitates management of this source of water so it not depleted. The
results of the MGWS will be used by State and County governments to develop
ordinances to protect ground-water supplies in western Jefferson County.
5. Class V Wells: Protecting the Missoula Valley Aquifer
From 1990 to 1993, the EPA awarded grant monies to the Missoula City and County
Health Department to study the sources of widespread chemical contamination in the
Missoula Valley aquifer. The ground-water contamination was caused by shallow
disposal systems, also called Class V wells (which include septic systems, storm drains,
dry wells, and cesspools). In 1986, tetrachloroethylene (perc or PCE), a solvent used in
dry cleaning processes, had been detected in fifteen of the City's water wells. Three of
these wells had PCE concentrations exceeding EPA's drinking water standards and had
to be shut down. The Disposal System Initiative encouraged local government officials,
private business owners, and concerned citizen groups to collaboratively protect their
sole source of drinking water. They agreed to several actions including: 1) the closure of
over 300 shallow disposal systems without a single facility going out of business; 2) the
development of innovative, cost-effective, and environmentally sound waste reduction
and disposal alternatives to using shallow disposal systems; and 3) the establishment and
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enforcement of a City/County-wide ordinance prohibiting the use of shallow disposal
systems. As a result, the amount of contaminants entering the Missoula Valley aquifer
were dramatically reduced and the three supply wells were reopened. PCE detections in
wells were reduced from a high of twelve wells in 1989 to no wells in 1997.
6. Principal Aquifer Studies: Salt Lake City, Utah
The Salt Lake Valley, a large inter-montane valley, is home to the largest population
center in Utah. The Valley is underlain by a major aquifer, referred to as the Principal
Aquifer, comprised of a few hundred feet of unconsolidated valley-fill deposits. The
aquifer supplies water to thousands of domestic, commercial and industrial wells and to
more than 200 public drinking water wells. Because this aquifer supplies drinking water
to a large population, and the aquifer is situated beneath the metropolitan area, the
UDEQ and local water suppliers have long been aware of the need to adequately
characterize and protect this valuable ground-water supply. Numerous studies have been
completed to characterize the aquifer and guide management and protection efforts. The
hydrology, geology and water chemistry of the Principle Aquifer has been characterized
in more detail than most of the major aquifers within Region 8.
The Utah DWSP Program requires that PWSs delineate protection zones for their
ground-water sources. These protection zones are based on ground-water travel time or
hydrogeologic boundaries. The USGS assisted the water suppliers to estimate these
travel-time zones for the Principle Aquifer. The USGS determined the hydrologic
properties necessary to estimate ground-water velocity in the Principal Aquifer in the
southeast part of the Valley and described the hydrogeology of the recharge areas and
water quality of the Principal Aquifer.
In response to the Utah DWSP Program requirements, wellhead protection areas
(WHPAs) were delineated for nine of the major water suppliers in the Valley. This
project included 129 existing and planned public supply wells. For this delineation
project, the ground-water modelers started with a previously-developed USGS model,
then modified the model to obtain sufficient detail in order to estimate the smaller travel-
time zones near the wells. The available data and the significant conceptual
understandings of the Principle Aquifer permitted the modelers to accurately delineate
the WHPAs. Thus, the cumulative hydrogeologic characterization of the Principle
Aquifer has proven to be a critical element in the management of ground-water resources
within the Salt Lake Valley as local protection measures have been applied to the
WHPAs determined from these efforts.
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V. MEETING THE CHALLENGES OF GROUND-WATER
MANAGEMENT IN REGION 8
CONCLUSIONS
1. Aquifer Studies. In the Region 8 states, the major aquifers and aquifer systems have
been delineated and their geology and hydrology fairly well characterized. In general, aquifers
in Colorado and Montana are not as well characterized as in the other Region 8 states. However,
much remains to be done to fully characterize ground-water quality conditions and ground-
water/surface-water interactions of these systems.
2. Ground-Water Availability. The amount of ground water available for human use
has decreased significantly over the past 50 years due to over-exploitation. The United Nations
has warned that by the year 2025, more than two-thirds of the world's population will live with
significant water-shortage problems. Within Region 8, there are some locations, such as the
southern part of the Denver Basin, where ground water is being "mined," or withdrawn, at a
faster rate than it is replaced. As the use of ground water increases within the Region, the risk of
"mining" will also increase. Adequate supplies for all desired uses will be reduced as increased
demands occur in the semi-arid climate of the west, where recharge is slow. Declines in aquifer
water levels can also have a negative impact on.the ability of ground water to sustain
ecosystems. It is very important for resource managers at the local, state and federal levels to
recognize that ground-water supplies are finite. Future management and use of ground-water
resources will be constrained by the limited amount of recharge and storage.
3. Ground-Water Use. There has been a tremendous population growth in the Rocky
Mountain states from 1990 to 2000, particularly in parts of Colorado (30.6 % growth between
1990 and 2000), Utah (29.6 %) and Montana (14%). This growth has been supported in large
part by the increased use of ground water for drinking water supplies. In Utah, approximately
38% of all 1995 fresh ground water withdrawals were used for public supply needs, up more
than 20 % from the 1960s. In addition, growing municipal and public supply demands are
shifting water use away from agricultural uses to municipal water use (Moore and others, 1990).
The rural west is almost 100% dependent on ground water for drinking water, and it is becoming
increasingly important for private domestic drinking-water supplies. Between 1990 and 1995,
the number of people relying on ground water for domestic uses in Region 8 increased by about
230,000; roughly 70% of these residents are served by private wells. Growth in rural areas will
probably continue to be a major source of increased ground-water use.
4. Ground-Water Contamination. Ground-water quality data indicate that many of the
surficial, unconsolidated aquifers in the western states are being contaminated by a variety of
land uses. Waste disposal, agricultural land uses, mining and urbanization have had the greatest
impact on ground-water quality. Since 1976, state and federal environmental protection
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agencies have implemented a variety of programs to correct past waste disposal practices and to
clean up a number of existing ground-water contamination problems at some of the worst waste
disposal sites. However, to date, there has not been the same success in managing non-point
sources of ground-water contamination which rely heavily on the use of voluntary best
management practices. The effectiveness of these programs is difficult to evaluate.
It is generally assumed that ground water is safe for consumption without treatment. However,
much of the ground water in the Rocky Mountain West may require treatment to meet Safe
Drinking Water Act drinking water standards unless federal, state and tribal agencies, local
governments, industry and landowners dedicate themselves to protect ground-water resources in
the future. Treatment requirements will create a financial burden for individual domestic well
users as well as communities dependent upon ground water.
5. Ground-Water Management Programs. Currently ground-water management is
highly fragmented: that is, different water supply and water quality agencies within federal, state
and local governments have a variety of regulatory and non-regulatory responsibilities. This
fragmentation makes it very difficult to effectively manage the resource. For example, within
Region 8, permits to construct water supply wells are issued by each State Engineer's Office.
However, local governments typically have the responsibility to assure that there is adequate
availability of water to support proposed land uses. This is problematic since local land use
authorities are not always compatible with sustainable ground-water management.
Management of ground-water quality is typically the responsibility of State Health Departments
or State Departments of Environmental Quality, while the federal government has had limited
direct responsibilities. However, EPA, in partnership with state governments, is typically
responsible for ground-water cleanup at hazardous-waste sites which are being addressed under
Superfund and RCRA. EPA also has oversight responsibility for state ground-water
management programs funded by the Safe Drinking Water Act and the Clean Water Act. These
management programs apply primarily to public water supplies. Consequently, private domestic
water supplies are not protected other than by limited, local regulations that may require testing
before sale of the property. EPA commonly provides technical and scientific support to state
ground-water management programs. Similarly, the United States Geological Survey plays a key
role in characterizing and monitoring ground-water resources and providing technical support to
state programs.
State Health Department and EPA ground-water staff have been reduced over the past 10-15
years. The financial and technical capacity to deal with ground-water protection and
management has been eroded, and coordination between ground-water management agencies
and programs has decreased. As a result, there has not been a focus on the resource, but on the
narrow issues that each agency/program deals with. Coordination between ground-water and
surface-water programs/agencies is minimal.
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RECOMMENDATIONS
1. Ground-Water Management Should Be Aquifer-Based. Just as surface water
is characterized, mapped and managed on a stream-by-stream, lake-by-lake, or watershed basis,
ground water should be managed on an aquifer and aquifer-system basis. Aquifers are the
natural units of management for ground water just as a stream, lake or watershed is a natural unit
of management for surface water.
It is quite common for a single aquifer to underlie multiple jurisdictions. Ground-water
management often proceeds without all parties recognizing that they are managing the same
aquifer. This has resulted in a fragmented, often ineffective, and sometimes contradictory, non-
resource-based approach to ground-water management. There is enough knowledge and
understanding of aquifers and aquifer systems to adopt a fundamental shift to aquifer
management.
Effective ground-water protection and management relies on recognition by state and local
governments that surface water and ground water are hydraulically connected. Watershed
management has typically ignored the connection between ground water and surface water, even
though ground water can be a critical factor with regard to both the quantity and quality of
streams and lakes. Integration of ground-water management and surface-water management at
the state and local level is critical
2. Monitoring Should Be A Key Element Of Ground-Water Management.
There are insufficient data to truly determine the status of ground-water quality for most major
aquifers and aquifer systems in Region 8. While there are many monitoring efforts conducted by
numerous agencies, there is little consistency in monitoring programs, data are not shared
effectively among the programs, various entities are often not aware of monitoring by others,
many of the data are not entered on computer databases, and many databases are not compatible.
Also, the amount of monitoring being done is very limited relative to the size of the resource.
The result is a patchwork of data useful for informed management decisions on a localized, site-
specific level, but of less value for making state- or region-wide conclusions about status and
trends.
An up-to-date assessment of the existing data is needed in each Region 8 state to identify data
needs so that a more comprehensive, coordinated ground-water monitoring network can be
developed to focus on monitoring high-priority aquifers or regions. Analytical parameters
should include selected indicator parameters that are common to all monitoring locations and
individual parameters that are important locally and should include water-use data. These
ground-water monitoring programs should be coordinated and funded by state and federal
agencies. The U.S. Geological Survey, in cooperation with the EPA, should also be funded to
prepare National Water Quality Summaries (for major aquifers/aquifer systems in each state)
every 5 years. These assessments have been previously prepared under Clean Water Act
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authorities; however, the last assessment was in 1986. The future compilation of these
assessments is currently uncertain.
The USGS National Water Quality Assessment Program (NAWQA) is one of the few federal
programs that is evaluating ground-water quality nationally. The NAWQA assessments being
conducted in Region 8 offer valuable information about ground-water quality and trends as the
Program's efforts progress in selected watersheds. The NAWQA Program and other key ground-
water quality studies should be fully supported by the appropriate state and federal agencies.
Appendix C gives the web sites describing each study in the Program within Region 8.
3. Prevention of Contamination Is More Effective Than Cleanup. Because
cleaning up aquifers after they are contaminated is difficult and expensive, preventing
contamination is much more sensible than trying to clean it up. Ironically, federal and state
governments spend hundreds of millions of dollars per year on ground-water remediation, and
only a few million dollars per year on prevention of contamination. Nationally, the average
capital costs for ground-water remediation systems range from a low of approximately $500,000
for passive systems to a high of about $3,500,000 for pump-and-treat systems (USEPA 1999b
and USEPA 2001). Annual operating costs for such systems add an average cost of
approximately $70,000 to $700,000 per year. Significantly more money should be allocated to
prevention efforts, including;
* public education regarding how contamination occurs;
• assessments of sensitivity and vulnerability of aquifers and ground water;
well-head protection/source-water assessment and protection;
management of recharge areas; and
• ambient monitoring to determine water quality trends.
Individual sewage disposal systems (ISDS) or septic tanks are often improperly installed and
managed. With the recent population growth in rural areas of Region 8, the number of ISDS is
increasing dramatically. Many local health departments are concerned about potential
contamination of ground water if ISDS leak. Furthermore, within the fractured rock settings of
the Rocky Mountains and the Colorado Plateau, the traditional ISDS design is often not suitable
and is more prone to failure than ISDS installed in other hydrogeologic settings. This is due
primarily to tjie typically thin soils and high degree of preferential flow in these settings. Most
ISDS are designed and constructed to operate effectively in thick soil, porous media
hydrogeologic settings. A new approach is needed for regulating septic-tank design, installation
and maintenance that recognizes the limitations of fractured rock settings in the Rocky
Mountains and the Colorado Plateau.
4. Non-Point Source Contamination Of Ground Water Is Still A Significant
Problem. Federal, state and local governments have made insufficient progress in establishing
effective programs aimed at reducing non-point source contamination. The most common non-
point source contaminants include agricultural chemicals, sediment and urban runoff.
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EPA made the following recommendations related to non-point source contamination of
ground-water resources in a 1994 report to Congress (U.S.EPA 1995):
Pesticides and fertilizers should be applied only according to label instructions;
Site-specific assessment should be conducted to accurately identify and protect
vulnerable ground water;
• Ground-water recharge areas and wellhead areas should be identified and
protected;
• Flood irrigation should be used more carefully.
While these are common-sense recommendations, they rely on mainly voluntary measures and
best management practices. There are no data that demonstrate that voluntary measures have
been effective across Region 8.
5. Effective Ground-Water Management Requires Adequate Funding.
Currently, ground-water characterization, monitoring and management is inadequately funded
throughout most of the country^ including EPA Region 8. As ground-water development and
use increases in Region 8 and elsewhere, it will be necessary to strengthen the commitment to
sustainable development. In the future, federal, state and local governments will face serious
issues related to providing a safe, sustainable water supply to satisfy beneficial uses. Tough
decisions will be required related to choosing between protection versus remediation of ground
water, and mining of ground-water resources vs. sustainable development. To address these
management issues, it is vital to provide adequate funding for ground-water/aquifer
characterization, monitoring and conjunctive management of ground water and surface water.
CURRENT ISSUES IN GROUND-WATER MANAGEMENT
1. Microorganisms in Ground Water. Research has recently revealed a better
understanding of the occurrence and fate of microorganisms in ground water. A wide variety of
microorganisms (such as bacteria, viruses and parasites) occur in the subsurface, including
pathogenic microorganisms. Contamination of ground-water public water supply systems by
pathogenic microorganisms has been implicated in several incidents of water-borne illnesses in
Region 8 during the past 5 years. Congress directed the EPA to promulgate a rule requiring
ground-water public water supply systems to develop barriers to contamination by pathogenic
microorganisms. The final Ground Water Rule is expected in 2003. See
www.epa.gov/safewater/protect/gwr/gwr.html for more information.
2. Organic Wastewater Contaminants. This group of products includes selected
Pharmaceuticals and personal care products including fragrances, dyes, antibiotics and other
medicines, caffeine, and hormones. These products have recently been detected in ground water
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(at sub-microgram per liter levels). Their extent of occurrence is unknown, as are the transport
and fate characteristics. Much remains to be learned before it is known if this group of products
will present a significant ground-water management problem. However, ongoing development
of analytical methodologies capable of detecting these products in water is helping to create the
capability to study their occurrence in ground water. The USGS has sampled for these products
in ground water in a few select areas within Region 8.
3. Fractured-Rock Aquifers. Large areas within Region 8 are underlain by fractured-
rock aquifers. It has long been recognized that ground-water occurrence and flow through
fractured rock is significantly different than ground-water flow through porous media such as
sand or gravel. However, the recent growth in the Rocky Mountains has stimulated interest in
better understanding ground-water occurrence, flow, quality and ground-water interaction with
surface water in a fractured-rock setting. Fractured-rock aquifers are limited in their ability to
yield adequate amounts of water to domestic wells. In mountainous settings, ground water in
fractured-rock aquifers is highly connected to surface water. Consequently, stream flows are
sensitive to over development of ground water. The hydrogeology of fractured-rock aquifers has
developed into an important research and management topic.
4. MTBE and Other Fuel Oxygenates. A new contaminant threat to ground water was
identified when the USGS discovered MTBE (methyl tertiary butyl ether) in ground-water
samples from monitoring wells in-the metro Denver area in the early 1990's. MTBE has been
used in U.S. gasoline at low levels (< 7 percent) since 1979 but was added at higher
concentrations (11-15 percent) in some gasoline nearly a decade ago to fulfill the oxygenate
requirements of the 1990 Clean Air Act. Studies have increasingly detected MTBE in ground
water throughout the country. Low levels of MTBE (20-40 ppb) can make drinking-water
supplies undrinkable due to its offensive taste and odor. The health effects of MTBE are being
studied (see www.epa.gov/mtbeA).
Numerous states and Congress are considering reducing or eliminating the use of MTBE to
protect water resources and public health. Such a ban could result in the use of substitute
oxygenates (e.g., ethanol, ETBE (ethyl tertiary butyl ether), TAME (tertiary amyl methyl ether),
TAEE (tertiary amyl ethyl ether), DIPE (diisopropyl ether), DME (dimethyl ether), and TBA
(tertiary butyl alcohol)) to comply with the Clean Air Act. Ethanol is already in widespread use,
for example, in the Denver area. However, oxygenates substituted for MTBE may have negative
effects on ground water. The environmental fate of substitute oxygenates released from leaking
underground storage tanks and other spills needs further investigation to assess threats to
ground-water quality.
5. Perchlorate (C1O4~). Perchlorate is both a naturally occurring and man-made chemical.
Most of the perchlorate manufactured in the U.S. (as ammonium perchlorate) is used as the
primary ingredient of solid rocket propellant; ammonium perchlorate is also used in certain
munitions, fireworks, the manufacture of matches, and analytical chemistry. Wastes from the
manufacture and improper disposal of perchlorate-containing chemicals are increasingly being
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discovered in water resources. The perchlorate anion can persist for many decades under typical
ground-water and surface-water conditions. In Region 8, the known releases of perchlorate to
ground water have been in Utah. However, additional inventory of potential facilities and/or
sites is needed where perchlorate chemicals have been used, stored, or disposed of in the Region.
According to EPA, perchlorate is a contaminant which requires additional research in the areas
of health effects, treatment technologies, analytical methods, and occurrence. Perchlorate is of
particular concern because it may be an endocrine disrupter and the current advisory limit in
drinking water is very low (2 ppb). See www.epa.gov/safewater/ccl/perchlorate/ for more
information.
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REFERENCES
Aller, L. T., Rennet, T., Lehr, J.H., Petty, RJ. 1987 A Standardized System for Evaluating
Ground Water Pollution Potential Using Hydrogeologic Settings. USEPA, RS Ken-
Environmental Research Laboratory, Ada, OK, EPA/600/287/035.
Alley, W.M., Reilly, I.E., Franke, O.L. 1999. Sustainability of Ground-Water Resources. U.S.
Geological Survey Circular 1186. Denver, CO.
Amundson, F.D. 2002. Estimated Use of Water in South Dakota, 2000. U.S. Geological
Survey Open-File Report 02-440.
ASTM, 1996. Standard Guide for Selection of Methods for Assessing Ground Water or Aquifer
Sensitivity and Vulnerability. American Society of Testing and Materials. D6030-96.
Http://www.astrn.org
Coutlakis, Denise. 2000. EPA's Ground Water Report to Congress Under SDWA Section
1429-A Summary. Ground Water Monitoring Review. Spring, 2000.
Driscoll, F.G. 1986. Ground Water and Wells, Johnson Division.
Freeze, R.A., and Cherry, J.A. 1979. Groundwater. Chapters 3 and 7. Prentice-Hall Inc.
Ground Water Monitoring Review. 2001. Spring edition, Volume 21, #2.
Hamerlinck, J.D. and Arneson, editors. 1998. Wyoming Ground Water Vulnerability
Assessment Handbook: Volume 1. Background, Model Development, and Aquifer Sensitivity
Analysis. Spatial Data and Visualization Center Publication SDVC 98-01 -1. University of
Wyoming. Laramie, Wyoming.
Heath, R.C. 1983. Basic Ground-Water Hydrology: U.S. Geological Survey Water-Supply
Paper 2220.
Heath, R.C, 1984. Ground-Water Regions of the United States. U.S. Geological Survey Water-
Supply Paper 2242.
Hutchinson, M.M. 2002. Personal Communication, Statistics from State Source Water
Protection End-of-Year Reports for Fiscal Year 2000. USEPA Region 8.
Meinzer, Oscar. E. 1923. Outline of ground-water hydrology: USGS Water Supply paper 494,
71 p.
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Reetz, G.R. 1998. Water Quality in the West. Report to the Western Water Policy Review
Advisory Commission. USEPA Region 8, Denver, CO.
Robson, S.G., andBanta, E.R. 1995. Ground Water Atlas of the United States. Segment 2.
Arizona, Colorado, New Mexico, Utah. U.S. Geological Survey Hydrologic Investigations Atlas
730-C.
Russell, M.E., Colglazier, W., and English, M.R. 1991. Hazardous Waste Site Remediation:
The Task Ahead. Knoxville: University of Tennessee, Waste Management Research and
Education Institute.
Sampat,P. 2000. Deep Trouble; The Hidden Threat of Groundwater Pollution. Worldwatch
Paper #154. Worldwatch Institute. Http://www.worldwatch.org
Solley, W.B., Pierce, R.R., and Perlman, H.A. 1998. Estimated Use of Water in the United
States in 1995. U.S. Geological Survey Circular 1200. Http:///water.usgs.gov/public/watuse/
Thomas, Harold E. 1952. Ground-water Regions of the United States - their storage facilities:
Interior and Insular Affairs Committee, US House of Representatives, 76 p.
USEPA. 1990. Handbook of Ground Water, Volume 1: Ground Water and Contamination.
Chapters. EPA/625/6-90/016a.
USEPA. 1999a. Safe Drinking Water Act, Section 1429, Ground Water Report to Congress.
EPA-816-R-99-016. Http://www.epa.gov '
USEPA. 1999b. Groundwater Cleanup: Overview of Operating Experience at 28 Sites. EPA
542-R-99-006. September 1999.
USEPA. 2001a. Factoids: Drinking Water and Ground Water Statistics for 2000. EPA816-K-
01-004. Http://www.epa.gov/safewater/data/factoids.pdf
USEPA. 2001b. Cost Analyses for Selected Groundwater Cleanup Projects: Pump and Treat
Systems and Permeable Reactive Barriers. EPA 542-R-00-013, February 2001.
USEPA. 2003. 40 CFR Parts 9, 122, 123, 412. Preamble to the Final CAFO Rule.
USGS. 1985. Hem, J.D. Study and Interpretation of the Chemical Characteristics of Natural
Water. U.S.Geological Survey Water-Supply Paper 2254, Third Edition.
USGS. 1988. National Water Summary 1986-Hydrologic Events and Ground-Water Quality.
U.S. Geological Survey Water-Supply Paper 2325.
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Virgil, J., Warburton, S., Haynes, W.S., Naiser, L.R.. 1965. Nitrates in Municipal Water
Supply Cause Methemoglobinemia in Infant, Public Health Reports, Vol. 80, No. 12, p. 1119-
1121.
Whitehead, R.L. 1996. Ground Water Atlas of the United States. Segments. Montana, North
Dakota, South Dakota, Wyoming. U.S. Geological Survey Hydrologic Investigations Atlas 730-
I.
Winter, T.C., Harvey, J.W., Franke, O.L., Alley, W.M. 1999. Ground Water and Surface
Water, A Single Resource. U.S. Geological Survey Circular 1139. Denver, CO.
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APPENDIX A
GROUND-WATER GLOSSARY
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GROUND-WATER GLOSSARY
Abandoned well - a well whose use has been permanently discontinued or which is in a state of
disrepair so that it cannot be used for its intended purpose.
Acid mine drainage - drainage of water from areas that have been mined for coal or other
mineral ores; the water has low pH because of its contact with sulfur-bearing material and is
harmful to aquatic organisms.
Adsorption - removal of a pollutant from air or water by collecting the pollutant on the surface
of a solid material.
Agricultural pollution - farming wastes, including runoff and leaching of pesticides and
fertilizers, erosion and dust from plowing, improper disposal of animal manure and carcasses,
crop residues, and debris.
Alluvium - a general term for clay, silt, sand, gravel, or other unconsolidated material deposited
by a stream or other body of running water; the term applies to stream deposits of recent time.
Adjective: alluvial.
Ambient water quality - describing the chemical, physical, and biological characteristics of
water as monitored beyond the immediate influence of human activities.
Anisotropy - the conditions under which one or more hydraulic properties of an aquifer vary
from-a reference point.
Aquifer - an underground geologic formation, group of formations, or part of a formation that
contains sufficient saturated permeable material-to yield significant quantities of water to wells
and springs.
Aquifer test - a test involving the withdrawal of measured quantities of water from, or addition
of water to, a well (or wells) and the measurement of resulting changes in head in the aquifer
both during and after the period of discharge or addition in order to determine hydraulic
properties of an aquifer.
Aquitard - an underground geologic formation that is slightly permeable and yields minor
amounts of water in comparison to an aquifer; may function as a confining bed.
Arid climate - term applied to an area where the climate is dry, usually considered as areas with
precipitation less than 10 inches per year.
Artificial recharge - recharge by deliberate or incidental actions of man.
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Atmosphere - the gaseous layer that surrounds the earth. Synonym: air.
Attenuation - the process by which a compound is reduced in concentration over time, through
absorption, adsorption, degradation, dilution, and/or transformation.
Bedrock - a general term for any consolidated rock.
Biodegradable - capable of decomposing under natural conditions.
Bioremediation - use of living organisms to clean up oil spills or remove other pollutants from
soil, water, or wastewater.
Brackish - mixed fresh and salt water.
Brine - a solution containing appreciable amounts of NaCI and other salts
Capillary fringe - a zone in the soil just above the water table that remains saturated or almost
saturated by water under less than atmospheric pressure.
Community water supply - a public water system which serves at least 15 service connections
used by year-round residents or regularly serves at least 25 year-round residents.
Concentration - the relative amount of a substance mixed with another substance; e.g., 1
milligram of iron per 1 liter of water or 1 mg/1.
Condensation - the process in which water vapor is cooled to the liquid phase.
Cone of depression - a depression in the water-table surface around a well, or group of wells,
from which water is being drawn. Synonym: cone of influence.
Confined aquifer - an aquifer whose upper boundary is defined by a layer.of geologic material
that does not transmit water readily (see "aquitard"), resulting in the ground water in the aquifer
being confined under pressure significantly greater than atmospheric pressure. Synonym:
artesian aquifer.
Confining layer - geologic material through which significant quantities of water cannot move.
Synonyms: aquitard, confining bed.
Contaminant - any physical, chemical, biological, or radiological substance or matter that has an
adverse effect on air, water, or soil.
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Contamination - introduction into water, air, and soil of microorganisms, chemicals, toxic
substances, wastes, or wastewater in a concentration that makes the medium unfit for its next
intended use.
Contamination source inventory - an inventory of potential contaminant sources within
delineated source water protection areas.
Cuttings - spoils left from drilling boreholes and/or wells.
Dense non-aqueous phase liquid (DNAPL) - non-aqueous phase liquids such as chlorinated
hydrocarbon solvents or petroleum fractions with a specific gravity greater than 1.0. These
liquids sink through the water column until they reach a confining layer. Because they are at the
bottom of aquifers instead of floating on the water table, typical monitoring wells may not
indicate their presence.
Discharge area - an area in which subsurface water, including both ground water and water in
the unsaturated zone, is discharged to the land surface, to a surface water, or to the atmosphere.
Dispersion - the spreading and mixing of chemical constituents in ground water caused
primarily by mixing due to microscopic variations in water flow rates within and between pores.
Downgradient - the direction that ground water flows; similar to "downstream" for surface
water.
Drainage well -. a well drilled to carry excess water off agricultural fields; because they act as a
conduit from the land surface to the ground water, drainage wells can contribute to ground-water
pollution.
DRASTIC - EPA methodology used to evaluate the sensitivity of an aquifer that considers 1)
depth to ground water, 2) recharge, 3) aquifer matrix, 4) soil type, 5) topography, 6) impact of
the vadose zone, and 7) hydraulic conductivity.
Drawdown - the drop in the water table or level of water in the ground when water is being
pumped from a well; the difference between the water level in a well before pumping and water
level in a well during pumping.
Evaporation - the process in which liquid water is transferred into the atmosphere from the soil
and surface-water bodies.
Evapotranspiration - the combined loss of water to the atmosphere from land and water surfaces
by evaporation and from plants by transpiration.
Extraction well - a discharge well used to remove ground water or air.
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Feedlot - a confined area for the controlled feeding of animals (CAFO) that tends to concentrate
large amounts of animal waste that cannot be absorbed by the soil. The waste may be carried to
nearby streams or lakes by rainfall runoff or may percolate into the underlying ground water.
Flow line - the path that a particle of water follows in its movement through saturated,
permeable rocks.
Fresh water - water that generally contains less than 1,000 milligrams per liter of dissolved
solids (USGS). •
Geological log - a detailed description of all underground features (depth, thickness, type of
formation) discovered during the drilling of a well.
Ground-water discharge - the removal of water from the saturated zone across the water-table
surface, together with the associated flow toward the water table within the saturated zone.
Ground water- that part of the subsurface water in the saturated zone.
Ground-water divide - a ridge in the water table or potentiometric surface from which ground
water moves away in both directions.
Ground-water flow system - flow of ground water from areas of recharge to areas of discharge.
Head - the height above a standard datum of the surface of a column of water (or other liquid)
that can be supported by the static pressure at a given point,
Heavy metals - metallic elements with high atomic weights (eg., mercury, chromium, cadmium,
arsenic, and lead); can damage living things at low concentrations and tend to accumulate in the
food chain.
Hollow-stem auger drilling - conventional drilling method that uses augers to penetrate the soil;
as the augers are rotated, soil cuttings are conveyed to the ground surface via auger spirals.
Hydraulic connection - a measure of the degree of potential interchange of ground water
between adjacent aquifer units.
Hydraulic conductivity - the rate at which water can move through a permeable media; a
measure of the ease with which a fluid will pass through a porous material, determined by size
and shape of the pore spaces in the material and their degree of interconnection as well as by the
viscosity of the fluid.
Hydraulic head - the sum of the elevation head and pressure head at a given point in an aquifer.
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Hydraulic gradient - in general, the direction of ground-water flow due to changes in the depth
of the water table; the change in hydraulic head per unit of distance in a given direction.
Hydraulic testing - a methodology employed to determine the various physical properties of an
aquifer to transmit and store water. Synonym: pumping test.
Hydrogeology - the geology of ground water, with particular emphasis on the geologic
environment of ground water.
Hydrologic cycle - movement or exchange of water between the atmosphere and earth; the
circulation of water in and on the earth and through earth's atmosphere through evaporation,
condensation, precipitation, runoff, ground-water storage and seepage, and re-evaporation into
the atmosphere. Synonym: water cycle.
Hydrology - the science dealing with the properties, distribution, and circulation of water.
Impermeable - the property of a material or soil that does not allow, or allows only with great
difficulty, the passage of water.
Individual sewage disposal system (ISDS) - see "septic system".
Infiltration - the downward entry of water through the land surface into the underlying soil or
sediment.
Infiltration rate - the quantity of water that can enter the soil in a specified time interval.
Injection well - a well into which fluids are injected for purposes such as waste disposal,
improving recovery of crude oil, or solution mining.
Inorganic chemicals - chemical substances of mineral origin with no organic elements.
Irrigation - applying water or wastewater to land areas to supply the water and nutrient needs of
plants.
Irrigation return flow - surface and subsurface water which leaves the field following
application of irrigation water.
Karst - a geologic formation of irregular limestone deposits with sinks, underground streams,
and caverns.
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Landfills - sanitary landfills are disposal sites for non-hazardous solid wastes spread in layers,
compacted to the smallest practical volume, and covered by material applied at the end of each
operating day; secure chemical landfills are disposal sites for hazardous waste, selected and
designed to minimize the chance of release of hazardous substances into the environment.
Leachate - water that collects contaminants as it trickles through wastes, pesticides, or
fertilizers; leaching may occur in farming areas, feedlpts, and landfills and may result in
hazardous substances entering surface water, ground water, or soil.
Leaching - the process by which soluble constituents are dissolved and filtered through the soil
by a percolating fluid.
Light non-aqueous phase liquid (LNAPL) - a non-aqueous phase liquid with a specific gravity
less than 1.0 such as most common petroleum hydrocarbon fuels and lubricating oils; because
the specific gravity of water is 1.0, most LNAPLs float on top of the water table.
Lithology - mineralogy, grain size, texture, and other physical properties of granular soil,
sediment, or rock.
Maximum Contaminant Level (or MCL) - the maximum concentration of a specific contaminant
that is allowed in public drinking water.
Mining of an aquifer - withdrawals of ground water over a period of time in excess of natural
recharge and capture. Synonym: overdraft.
Mining waste - residues resulting from the extraction and processing of raw materials from the
earth.
Monitoring - periodic or continuous surveillance or testing to determine the level of compliance
with statutory requirements and/or pollutant levels in various media or in humans, plants, and
animals,
Monitoring well - a well used to obtain water quality samples or measure ground-water levels.
Nitrate - a compound (NO3) containing nitrogen that can exist in the atmosphere or as a
dissolved ion in water and which can have harmful effects on humans and animals; a plant
nutrient and inorganic fertilizer, nitrate is found in septic systems, animal feedlots, agricultural
fertilizers, manure, industrial waste waters, sanitary landfills, and garbage dumps,
Non-aqueous phase liquid (NAPL) - contaminants that remain undiluted as the original bulk
liquid in the subsurface; eg., spilled oil.
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Non-community water system - a public water system that is not a community water system;
eg., the water supply at a camp site or national park.
Non-point sources - diffuse pollution sources (i.e., without a single point of origin or not
introduced into a receiving stream from a specific outlet) generally carried off the land by storm
water runoff; common non-point sources are agriculture, forestry, urban, mining, construction,
dams, channels, land disposal, saltwater intrusion, and city streets.
Non-potable - water that is unsafe or unpalatable to drink because it contains pollutants,
contaminants, minerals, or infective agents (e.g. bacteria, viruses, etc.).
Non-transient, non-community water system - a public water system that regularly serves at
least 25 of the same non-resident persons per day for more than six months per year.
Organic chemicals/compounds - animal- or plant-produced or synthetic substances containing
mainly carbon, hydrogen, nitrogen, and oxygen.
Organism - any form of animal or plant life.
Overburden - rock and soil cleared away before mining.
Overdraft - the pumping of water from a ground-water basin or aquifer in excess of the supply
flowing into the basin; results in a depletion or mining of the ground water. Synonym: mining
of ground water.
Parts per billion (ppb) / parts per million (ppm) - units commonly used to express contamination
ratios, as in establishing the maximum permissible amount of a contaminant in water, land, or
air.
Pathogens - microorganisms (eg., bacteria, viruses, or parasites) that can cause disease in
humans, animals, and plants.
Perched ground water - unconfmed ground water separated from an underlying main body of
ground water by an unsaturated zone; zone of pressurized water held above the water table by
impermeable rock or sediment; often a result of clay lenses in the soil.
Percolation - the movement of water downward and outward through subsurface soil layers,
sometimes continuing downward to ground water.
Permeable - the degree to which the pore or void spaces in soils and rock are interconnected; if
spaces in rocks are connected and large enough that water, other liquids, or air can move freely
through them, the rock is said to be permeable; eg., sand is more permeable than clay because
the pore spaces between sand grains are larger than pore spaces between clay particles.
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Permeability - the rate at which liquids or air pass through soil or other materials in a specified
direction.
Pesticide - substance intended for preventing, destroying, repelling, or mitigating any pest; any
substance or mixture intended for use as a plant regulator, defoliant, or desiccant.
Piezometer - a nonpumping well, generally of small diameter, for measuring the elevation of the
water table.
Plume - a visible or measurable discharge of a contaminant from a given point of origin; can be
chemical or thermal in water.
Point source - a stationary location or fixed facility from which pollutants are discharged; any
single identifiable source of pollution (eg., a pipe, ditch, ore pit, factory smokestack, etc.).
Pollutant - any substance introduced into the environment that adversely affects the usefulness
of a resource or the health of humans, animals, or ecosystems.
Pollution - the presence of a substance in the environment that because of its composition or
quantity prevents the functioning of natural processes and produces undesirable environmental
and, health effects.
Porosity - the degree to which the total volume of soil, gravel, sediment, or rock has pores or
cavities through which fluids (including air) can move.
Potable water - water that is safe for drinking and cooking.
Potentiometric surface - the surface to which water in an aquifer can rise by water pressure; an
imaginary surface representing the static head of ground water, of which the water table is one
type.
Precipitation - moisture falling from the atmosphere in the form of rain, snow, sleet, or hail.
Prior appropriation - a doctrine of water law that allocates the rights to use water on a first-
come, first-served basis.
Private domestic water supply- a water source developed for use by a single residence.
Public water system - a system that provides piped water for human consumption to at least 15
service connections or regularly serves 25 individuals.
Public water supply - see "public water system".
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Pumping test - a test conducted to determine aquifer or well characteristics. Synonyms: aquifer
test, hydraulic test.
Quality assurance / quality control - a system of procedures, checks, audits, and corrective
actions to ensure that all EPA research design and performance, environmental monitoring and
sampling, and other technical and reporting activities are of the highest achievable quality.
Radioactive substances - substances that emit ionizing radiation.
Radon - a colorless naturally occurring, radioactive, inert gas formed by radioactive decay of
radium atoms in soil or rocks.
Raw water - intake water prior to any treatment or use.
Recharge - addition of water to the saturated zone, usually by infiltration and percolation from
the soil surface.
Recharge area - a land area in which water that is infiltrated eventually reaches the saturated
zone.
Recharge rate - the quantity of water per unit time that replenishes or refills an aquifer.
Remediation - cleanup or other methods used to remove or contain a toxic spill or hazardous
materials from a site.
Riparian rights - entitlement of a land owner to certain uses of water on or bordering the
property, including the right to prevent diversion or misuse of upstream waters.
River basin - the land area drained by a river and its tributaries.
Runoff- that part of precipitation, snow melt, or irrigation water that runs off the land into
streams or other surface water; the flow of water from the land to oceans or interior basins by
overland flow and stream channels.
Safe water - water that does not contain harmful bacteria, toxic materials, or chemicals and is
considered safe for drinking even if it may have taste, odor, color, and certain mineral problems.
Safe yield - the amount of ground water that can be withdrawn from a basin annually without
producing an undesired result.
Salinity - the percentage of salt in water.
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Salts - minerals that water picks up as it passes through the air, over and under the ground, or
from households and industry.
Saturated zone - the area below the water table where all open spaces are filled with water under
pressure equal to or greater than that of-the atmosphere; a subsurface zone in which all the open
spaces are filled with water under pressure greater than atmospheric; the upper surface of the
saturated zone is the water table.
Secondary maximum contaminant level (or SMCL) - the maximum concentration of a specific
contaminant that is recommended in public drinking water based on aesthetics.
Seepage - percolation of water through the soil from unlined canals, ditches, laterals,
watercourses, or water storage facilities.
Semi-arid climate - term applied to an area where the climate is intermediate between arid and
humid, usually considered as areas with precipitation ranging from 10 to 20 inches per year.
Semi-confined aquifer - an aquifer partially confined by soil layers of low permeability through
which recharge and discharge can still occur.
Septic system - an on-site system designed to treat and dispose of domestic sewage; a typical
septic system consists of a tank that receives waste from a residence or business and a system of
tile lines or a pit for disposal of the liquid effluent that remains after decomposition of the solids
by bacteria in the tank. Synonym: individual sewage disposal system.
Septic tank - an underground storage tank for wastes from homes not connected to a sewer line.
Sewage - the waste and wastewater produced by residential and commercial sources and
discharged to sewers or septic systems.
Soft water - any water that does not contain a significant amount of dissolved minerals such as
salts of calcium or magnesium.
Solubility-the amount of mass of a compound that will dissolve in a unit volume of solution.
Source water protection area - the area delineated by a state for a public water supply or
including numerous such suppliers, whether the source is ground water or surface water or both.
Specific yield - the amount of water a unit volume of saturated permeable rock will yield when
drained by gravity.
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Spring - a concentrated discharge of ground water appearing at the ground surface as a current
of flowing water.
Standards - norms that impose limits on the amount of pollutants or emissions produced; EPA
establishes minimum standards, but the States or Tribes are allowed to be stricter.
Static water levels - elevation or level of the water table in a well.
Storage - water stored in an aquifer or other geologic unit.
Stratification - separating into layers.
Stratigraphy- study of the formation, composition, and sequence of sediments, whether
consolidated or not.
Surface runoff- precipitation, snow melt, or irrigation water in excess of what can infiltrate the
soil surface and be stored in small surface depressions; a major transporter of non-point source
pollutants into rivers, streams, or lakes.
Surface water - all water naturally open to the atmosphere and found over the land surface in
streams, ponds, and wetlands.
Susceptibility analysis - an analysis to determine whether a public water supply is subject to
significant pollution from known potential contaminant sources.
Tailings - residue of raw material or waste separated out during the processing of mineral ores.
Transient water system ~ a non-community water system that does not serve 25 of the same
nonresidents per day for more than six months per year.
Transmissivity - a measure of the ability of an aquifer to transmit water.
Transpiration - the process by which water passes through living organisms, primarily plants,
and into the atmosphere.
Treatment - any method, technique, or process designed to remove solids and/or pollutants from
solid waste, waste streams, effluents, and air emissions.
Turbidity - a cloudy condition in water due to suspended silt or organic matter.
Unconfmed aquifer - an aquifer whose upper boundary is the water table; an aquifer containing
water that is not under pressure. Synonym: water-table aquifer.
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Unsaturated zone - the area above the water table where pores are not fully saturated, although
some water may be present; a subsurface zone containing water under pressure less than that of
the atmosphere, including water held by capillarity, and containing air or gases generally under
atmospheric pressure; limited above by the land surface and below by the water table. Synonym:
vadose zone.
Vadose zone - the zone between land surface and the water table within which the moisture
content is less than saturation and pressure is less than atmospheric; the capillary fringe is
included in the vadose zone. Synonym: unsaturated zone.
Viscosity - the molecular friction within a fluid that produces flow resistance.
Water budget - the division of the water present within an aquifer or watershed into the major
components of the hydrologic cycle; these components are precipitation, runoff,
evapotranspiration, deep percolation, and change in storage. Synonym: water balance.
Watershed - all land and water within the confines of a drainage divide; the watershed for a
major river may encompass a number of smaller watersheds that ultimately combine at a
common point.
Water supply system - the collection, treatment, storage, and distribution of potable water from
source to consumer.
Water table - the upper surface of an unconfmed aquifer at which the pressure is atmospheric; it
is the level at which water stands in wells that penetrate the uppermost part of an unconfmed
aquifer.
Well - a bored, drilled, or driven shaft, or a dug hole whose depth is greater than the largest
surface dimension and whose purpose is to reach underground water supplies or oil or to store or
bury fluids below ground.
Wellfield - area containing one or more wells that produce usable amounts of water or oil.
Well point - a hollow vertical tube, rod, or pipe terminating in a perforated pointed shoe and
fitted with a fine-mesh screen.
Wellhead protection area - a protected surface and subsurface zone surrounding a well or
wellfield supplying a public water system. The zone is protected to keep contaminants from
reaching the well water.
Wetlands - an area that is saturated by surface water or ground water with vegetation adapted for
life under those soil conditions (also called swamps, bogs, fens, marshes, and estuaries).
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Yield - the quantity of water (expressed as a rate of flow or total quantity per year) that can be
collected for a given use from surface-water and ground-water sources.
REFERENCES FOR APPENDIX A
American Geological Institute, 1976. Dictionary of Geological Terms. Anchor Press, Garden
City, New York.
Driscoll, F.G., 1986. Groundwater and Wells. Johnson Division, St. Paul, Minnesota.
Freeze, R.A. and Cherry, J.A., 1979. Groundwater. Prentice-Hall, Englewood Cliffs, New
Jersey.
Harrold, L.L., Schwab, G.O., and Bondurant, B.L., 1982. Agricultural and Forest Hydrology.
Ohio State University, Columbus, Ohio.
Moore, J.E., Zaporozec, A., and Mercer, J.W., 1995. Groundwater - A Primer. American
Geological Institute, Alexandria, Virginia.
U.S. EPA, 1997. Terms of Environment - Glossary, Abbreviations, and Acronyms.
U.S. EPA Region 5, 1998. Ground Water Primer, www.epa.gov/seahome/gwprimer.html
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APPENDIX B
STATE AND EPA GROUND-WATER WEBSITES
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APPENDIX B
State and EPA Ground-Water Program Websites
COLORADO
The Department of Public Health and Environment, Water Quality Control Division is
responsible for ground water quality programs, including ground water quality monitoring,
CDPS groundwater discharge permits, and Source Water Protection. The Division has convened
a state ground water protection council comprised of all state agencies involved with ground
water protection.
http://www.cdphe.state.co.us/wq/wqhom.asp
The Office of the State Engineer, Division of Water Resources is responsible for ground water
quantity issues including well permits and water rights issues.
http://www.water.state.co.us/grnd.htm
MONTANA
The Department of Environmental Quality is responsible for several ground water quality
programs, including ground water remediation, Montana Ground Water Pollution Control
System permits, subdivision sanitary review, and the Source Water Protection Program. The
Department of Environmental Quality has a collaborative role in the Montana Ground Water
Plan.
http://www.deq.state.mt.us/wqinfo/index.asp
Department of Natural Resources and Conservation, Water Resources Division is responsible foi
the use, development, and protection of water resources, including ground water in Montana.
They are responsible for water well permitting, water rights, and the Montana Ground Water
Plan ( http://www.dnrc.state.mt.us/wrd/gw__plan.htm ).
http://www.dnrc.state.mt.us/wrd/home.htm
The Department of Agriculture is responsible for protecting ground water and the environment
from impairment or degradation due to the use or misuse of agricultural chemicals (pesticides
and fertilizers). The program includes ground water quality monitoring and public education.
http://www.agr.state.mt.us/programs/asd/groundh2o.shtml
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Information on Montana's ground water resources is available on line through the Montana
Natural Resource Information System.
http://nris.state.mt.us/wis/mtgwres.htm
NORTH DAKOTA
The Department of Health is responsible for the Ground Water Protection Program, including
ambient ground water quality monitoring, Source Water Protection, and Underground Injection
Control.
http://www.health.state.nd.us/ndhd/environ/wq/gw/gwindex.htm
The Department of Agriculture is responsible for developing the state's water protection strategy
for pesticides.
http://www.state.nd.us/agr/divisions.htmWpe
SOUTH DAKOTA
The Department of Environment and Natural Resources (DENR), Ground Water Quality
Program is responsible for managing ground water resources through oversight of clean up
efforts, ambient ground water quality monitoring, ground water discharge permits, the
Underground Storage Tank Program, the Underground Injection Control Programs, and Source
Water Assessment and Protection Programs.
http://www.state.sd.us/denr/DES/Ground/groundprg.htm
The DENR, Water Rights Program is responsible for ground water rights issues, water well
construction standards, technical assistance for proper plugging of abandoned wells, and the
observation well network.
http://www.state.sd.us/denr/des/waterrights/wr_organization.htm
Information about aquifers and ground water resources is available from the DENR Geological
Survey.
http://www.sdgs.usd.edu/index.html
UTAH
The Department of Environmental Quality (DEQ), Division of Water Quality's mission is to
protect and enhance the quality of Utah's ground and surface waters. Activities include ground
water permits for waste water discharges and UIC permits.
http://www.deq.state.ut,us/eqwq/Dwq_info.htm
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The DEQ, Division of Environmental Response and Remediation is responsible for the
Underground Storage Tank Program and ground water remediation.
http://www.deq.state.ut.us/EQERR/errhmpg.htm
The DEQ, Division of Drinking Water is responsible for the Drinking Water Source Protection
Program.
http://www.deq.state.ut,us/eqdw/source_protection_intro.htm
The Utah Department of Natural Resources (DNR), Division of Water Resources is responsible
for the management of water resources in Utah, including ground water. They have primary
responsibility for the Utah Water Plan, which includes management of ground water in the state.
http://www.nr.state.ut.us/wtrresc/Waterplan/uwrpff/TextOnly.htm
For information about ground water resources in Utah, contact the Utah DNR, Geological
Survey.
http://www.ugs.state.ut.us/
The UT DNR, Water Rights Division oversees the drilling of water wells. Resources include
water well logs for all wells more than 30 feet deep drilled in the state.
http://nrwrtl.nr.state.ut.us/wellinfo/default.htm
The Utah Department of Agriculture and Food, Agricultural Water Quality and Environmental
Programs is responsible for ground water quality issues related to agricultural practices and
chemicals.
http://ag.utah.gov/mktcons/nps.htm
AVYOMING
The Wyoming Department of Environmental Quality, Water Quality Division is responsible for
source water and wellhead protection, ground water vulnerability, subdivision planning, septic
systems, underground storage tanks, and underground injection control.
http://deq.state.wy.us/wqd.htm
The Wyoming State Engineer's Office, Division of Ground Water permits water wells in
Wyoming and manages a ground water data collection program, including well logs.
http://seo.state.wy.us/gw/gw.html
The Wyoming Department of Agriculture is responsible for water quality issues related to
agricultural practices.
http://wyagric.state.wy.us/ADMIN/wda.html
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US EPA WEBSITES
Main US EPA website
Region 8 website
General Information
http://www.epa.gov
http://www.epa.gov/region8/
Freedom of Information Act requests
Region 8
http://www.epa.gov/region08/foia/foia/html
Program-specific websites
Safe Drinking Water Act
General Information
http://www/epa.gov/safewater/
Sole Source Aquifer Program
http://www.epa.gov/safewater/ssanp.html
Underground Injection Control Program
http://www.epa.gov/safewater/uic.html
http://www.epa.gov/region8/water/uic/index.html
UIC Class V Program
http://www/epa.gov/safewater/uic/classv.html
Source Water Assessments and Protection, Wellhead Protection Programs
http://www.epa.gov/safewater/protect.html
http://www.epa.gov/region8/water/swap/index.html
Public Water Supply Supervision (Drinking Water) Program
http://www.epa.gov/safewater/pws/pwss.html
http://www.epa.gov/region8/water/dwhome/dwhome.html
Ground Water Rule
http://www.epa.gov/safewater/protect/gwrfs.html
National Drinking Water Contaminant Occurrence Database
http://www.epa.gov/ncod/
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Resource Conservation and Recovery Act - Solid and Hazardous Waste Programs
General Information
http://www.epa.gov/epaoswer/osw/index.htm
http://www.epa.gov/region08/] andjwaste/index.html
Hazardous Waste Program
http://www.epa.gov/epaoswer/osw/index.htm
http://www.epa.gov/region08/Iand_waste/rcra/rcrahwaste.html
Corrective Action Program
http://www.epa.gov/epaoswer/hazwaste/ca/index.htm
http://www,epa.gov/region08/land__waste/rcra/rcrahazclean.html
Municipal Solid Waste
http://www.epa.gov/epaoswer/non-hw/muncpl/laiidfill/index.htm
http://www.epa.gov/region08/land_waste/landfills/landfills.html
Underground Storage Tanks/Leaking Underground Storage Tanks
http://www.epa.gov/swerustl/index.htm
Comprehensive Environmental Response Compensation and Liability Act (Superfund)
General Information
http://www.epa.gov/superfund/
http://www.epa.gov/region08/superfund/
Clean Water Act
General Information
http://www.epa.gov/OW/
http://www.epa.gov/region08/water/
Non Point Source Program (Polluted Runoff)
http://www.epa.gov/owow/nps/
http://www.epa.gov/region08/water/nps/
TMDLs
http://www. epa.gov/owow/tmdl/
http://www.epa.gov/region08/water/tmdl/
Septic Systems
www. epa. go v/o wm/mtb/decent/index .htm
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APPENDIX C
USGS NAWQA SUMMARY
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USGS NAWQA SUMMARY
General USGS ground-water information may be found at http://water.usgs.gov/ogw. This
includes ground water data, publications, field methodologies, and links to other ground water
programs.
USGS DISTRICT OFFICES
http://co.water.usgs. go v
http://ut.water.usgs.gov
http ://mt. water, usgs. go v
http://nd.water.usgs.gov
http ://sd.water.usgs.gov
http://wy.water.usgs.gov
These websites have information on water resource investigations, real-time data, and drought /
flood information within each of these States.
The website for the USGS Water Resource Discipline's National Research Program is:.
http ://water.usgs. go v/nrp/
Information on current research activities as well as links to State water research activities can
be accessed.
USGS NAWQA SUMMARY
A general table of all the individual NAWQA study basins, their year of startup, and the States
covered may be found at:
http://water.usgs.gov/nawqa/nawqamap.htonlftTABLE
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