United States
Environmental Protection
Agency
Office of Water
Washington, DC 20460
EPA841-R-07-001
October 2007
http://www.epa.gov/305b
National Water Quality Inventory:
Report to Congress
2002 Reporting Cycle
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^Bl
Section 305 (b) of the Clean Water Act
This report was prepared pursuant to Section 305(b) of the Clean Water Act, which states:
(b) (1) Each State shall prepare and submit to the Administrator by April 1, 1975,
and shall bring up to date by April 1, 1976, and biennially thereafter, a report
which shall include—
(A) a description of the water quality of all navigable waters in such State
during the preceding year, with appropriate supplemental descriptions as
shall be required to take into account seasonal, tidal, and other variations,
correlated with the quality of water required by the objective of this Act
(as identified by the Administrator pursuant to criteria published under
section 304(a) of this Act) and the water quality described in subparagraph
(B) of this paragraph;
(B) an analysis of the extent to which all navigable waters of such State provide
for the protection and propagation of a balanced population of shellfish,
fish, and wildlife, and allow recreational activities in and on the water;
(C) an analysis of the extent to which the elimination of the discharge of
pollutants and a level of water quality which provides for the protection
and propagation of a balanced population of shellfish, fish, and wildlife
and allows recreational activities in and on the water, have been or will be
achieved by the requirements of this Act, together with recommendations
as to additional action necessary to achieve such objectives and for what
waters such additional action is necessary;
(D) an estimate of (i) the environmental impact, (ii) the economic and social
costs necessary to achieve the objective of this Act in such State, (iii) the
economic and social benefits of such achievement; and (iv) an estimate of
the date of such achievement; and
(E) a description of the nature and extent of nonpoint sources of pollutants,
and recommendations as to the programs which must be undertaken to
control each category of such sources, including an estimate of the costs of
implementing such programs.
(2) The Administrator shall transmit such State reports, together with an analysis
thereof, to Congress on or before October 1, 1975, and October 1, 1976, and
biennially thereafter.
•*^"i •**
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
Oct. 11, 2007
OFFICE OF
The Honorable Richard B. Cheney
President of the Senate
Washington, D.C. 20510
Dear Mr. President:
I am pleased to transmit the Environmental Protection Agency's (EPA) National Water Quality
Inventory: 2002 Report to Congress. Required by Section 305 (b) of the Clean Water Act, this report
summarizes, on a national basis, water quality assessment information reported to EPA by the states.
It is the hard copy companion to the National Assessment Database, an interactive, on-line database
of state water quality information which allows users to view assessment findings for individual states,
watersheds, and waterbodies.
This Report to Congress finds that, for the 2002 reporting cycle, the states assessed 19 percent of
the nation's 3.7 million river and stream miles, 37 percent of its 40.6 million acres of lakes, ponds and
reservoirs, and 35 percent of its 87,370 estuary square miles. Forty five percent of assessed river and
stream miles, 47 percent of assessed lake acres, and 32 percent of assessed estuary square miles were
found to be impaired for one or more of the uses designated by states, such as fishing or swimming.
Leading causes of impairment included nutrients, metals (primarily mercury), organic enrichment/
dissolved oxygen, sediment/siltation, and pathogens. Top known sources of impairment included
agriculture; hydrologic modifications such as water diversions and channelization; industrial sources;
atmospheric deposition; and municipal sources.
To get a good understanding of national water quality conditions and trends, EPA recommends the
use of probability surveys—scientifically-based studies designed to sample water quality conditions
at randomly selected sites that are statistically representative of the nation's many distinct ecological
regions. Therefore, this report also discusses the probability-based approach and the national studies of
coastal condition, fish tissue in lakes, and wadeable streams conducted by EPA and its partners. It also
discusses improvements underway in water quality reporting.
I would be pleased to further discuss the contents of this report at your convenience.
Sincerely,
Benjamin H. Grumbles
Assistant Administrator
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S^A,
Ss>
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
Oct. 11, 2007
The Honorable Nancy Pelosi
Speaker of the House
House of Representatives
Washington, D.C. 20515
Dear Madam Speaker:
I am pleased to transmit the Environmental Protection Agency's (EPA) National Water Quality
Inventory: 2002 Report to Congress. Required by Section 305 (b) of the Clean Water Act, this report
summarizes, on a national basis, water quality assessment information reported to EPA by the states.
It is the hard copy companion to the National Assessment Database, an interactive, on-line database
of state water quality information which allows users to view assessment findings for individual states,
watersheds, and waterbodies.
This Report to Congress finds that, for the 2002 reporting cycle, the states assessed 19 percent of
the nation's 3.7 million river and stream miles, 37 percent of its 40.6 million acres of lakes, ponds and
reservoirs, and 35 percent of its 87,370 estuary square miles. Forty five percent of assessed river and
stream miles, 47 percent of assessed lake acres, and 32 percent of assessed estuary square miles were
found to be impaired for one or more of the uses designated by states, such as fishing or swimming.
Leading causes of impairment included nutrients, metals (primarily mercury), organic enrichment/
dissolved oxygen, sediment/siltation, and pathogens. Top known sources of impairment included
agriculture; hydrologic modifications such as water diversions and channelization; industrial sources;
atmospheric deposition; and municipal sources.
To get a good understanding of national water quality conditions and trends, EPA recommends the
use of probability surveys—scientifically-based studies designed to sample water quality conditions
at randomly selected sites that are statistically representative of the nation's many distinct ecological
regions. Therefore, this report also discusses the probability-based approach and the national studies of
coastal condition, fish tissue in lakes, and wadeable streams conducted by EPA and its partners. It also
discusses improvements underway in water quality reporting.
I would be pleased to further discuss the contents of this report at your convenience.
Sincerely,
Benjamin H. Grumbles
Assistant Administrator
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Table of Contents
List of Figures ii
List of Tables ii
List of Acronyms ii
Executive Summary ES-1
Rivers and Streams ES-2
Lakes, Ponds, and Reservoirs ES-2
Bays and Estuaries ES-3
National Studies of Water Quality ES-3
Future Reporting ES-4
Background 1
About the National Assessment Database 2
Assessing Water Quality 4
Findings 7
Rivers and Streams 7
Lakes, Ponds, and Reservoirs 11
Bays and Estuaries 15
Other Waters 17
Coastal Resources 18
Great Lakes 19
Wetlands 20
National Studies of Water Quality 21
National Coastal Assessment 22
National Study of Chemical Residues in Lake Fish Tissue 25
Wadeable Streams Assessment 25
Assessing Lakes 28
Future Reporting 29
National Water Quality Inventory: Report to Congress
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List of Figures
1 Water quality in assessed river and stream miles 8
2 Water quality in assessed lake acres 11
*^m
3 Water quality in assessed bay and estuary square miles 15
4 Summary of the overall national coastal condition 24
5 Wadeable Streams Assessment sampling sites 26
6 Biological condition of wadeable streams
27
List of Tables
1 Individual Use Support in Assessed River and Stream Miles 8
2 Top Causes of Impairment in Assessed Rivers and Streams 9
3 Top Sources of Impairment in Assessed Rivers and Streams 10
4 Individual Use Support in Assessed Lake, Pond, and Reservoir Acres 12
5 Top Causes of Impairment in Assessed Lakes, Ponds, and Reservoirs 13
6 Top Sources of Impairment in Assessed Lakes, Ponds, and Reservoirs 14
7 Individual Use Support in Assessed Bay and Estuary Square Miles 15
8 Top Causes of Impairment in Assessed Bays and Estuaries 16
9 Top Sources of Impairment in Assessed Bays and Estuaries 17
List of Acronyms
BEACH Beaches Environmental Assessment and Coastal Health
EPA U.S. Environmental Protection Agency
FWS U.S. Fish and Wildlife Service
NOAA National Oceanic and Atmospheric Administration
PCBs polychlorinated biphenyls
TMDLs total maximum daily loads
USGS U.S. Geological Survey
National Water Quality Inventory: Report to Congress
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Executive Summary
Photo courtesy of JohnTheilgard
This National Water Quality Inventory: Report
to Congress, prepared under Section 305(b) of the
Clean Water Act, summarizes water quality reports
submitted electronically by the states and territories
to the U.S. Environmental Protection Agency
(EPA) for the 2002 reporting cycle. This state water
quality information is contained in EPA's National
Assessment Database for the 2002 reporting cycle,
available online at http://www.epa.gov/waters/305b.
For the first time, the National Assessment
Database provides the public with easy Internet
access to a wide range of state water quality
assessment results. The database contains summary
assessment information as reported electronically by
the states to EPA and includes a set of national tables
that summarize key water quality assessment findings
(as in previous Section 305(b) reports). Users can also
view assessments of individual waterbodies within
any state or watershed included in the National
Assessment Database, which presents data in a
format designed for quick reference by water quality
professionals and individuals familiar with water
quality reporting. The database also provides Internet
addresses for all the state water quality reports to
users interested in learning more about a particular
state's water quality protection program.
The key findings of the 2002 National Assessment
Database are presented in this report. It is important
to note that the information about specific sources
and causes of impairment is incomplete because the
National Water Quality Inventory: Report to Congress
ES-1
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Executive Summary
states do not always report the pollutant or source
of pollutants affecting every impaired waterbody. In
some cases, states may recognize that water quality
does not fully support a designated use; however,
they may not have adequate data to document
the specific pollutant or source responsible for the
impairment. In past national reports, unknown or
unspecified causes and sources were included only
as footnoted material to summary statistics. For the
first time, this report includes unspecified causes
and sources in all summary statistics to more clearly
represent what states are reporting to EPA.
Rivers and Streams
States assessed 19% of the nation's 3.7 million
miles of rivers and streams for the 2002 reporting
cycle. Of these waterbodies, 45% were reported
as impaired or not clean enough to support their
designated uses, such as fishing and swimming.
States found the remaining 55% to be fully
supporting of all designated uses. Sediment,
pathogens, and habitat alterations were cited as the
leading causes of impairment in rivers and streams,
and top sources of impairments included agricultural
activities, unknown/unspecified sources, and
hydrologic modifications (such as water diversions
and channelization).
Lakes, Ponds, and Reservoirs
States assessed 37% of the nation's 40.6 million
acres of lakes, ponds, and reservoirs during the
2002 reporting cycle. Of these waterbodies, 47%
were reported as impaired and 53% were fully
supporting all designated uses. Nutrients, metals
(primarily mercury), and organic enrichment/low
dissolved oxygen were cited as the leading causes
of impairment in lakes. Top sources of pollutants
to lakes, ponds, and reservoirs included unknown/
unspecified sources, agricultural activities, and
atmospheric deposition.
States assessed 19% of U.S. river and stream miles, and of those, 55% fully support
all designated uses, such as aquatic life harvesting and aesthetic value (Photo
courtesy of Luther Goldman, U.S. Fish and Wildlife Service).
ES-2
National Water Quality Inventory: Report to Congress
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Executive Summary
Bays and Estuaries
States assessed 35% of the nation's 87,370 square
miles of bays and estuaries for the 2002 reporting
cycle. Of these waterbodies, 32% were reported as
impaired and the remaining 68% fully supported
all designated uses. Metals (primarily mercury),
nutrients, and organic enrichment/low dissolved
oxygen were the leading causes of impairment in bays
and estuaries. Top sources of impairment to bays and
estuaries included unknown/unspecified sources,
industrial sources, and municipal discharges (e.g.,
sewage treatment plants).
States reported nutrients, metals, and organic
enrichment/low dissolved oxygen to be the leading
causes of impairment in lakes, ponds, and reservoirs
(Photo courtesy of Karen Rodriguez, EPA).
Boating, fishing, swimming, and bird watching are just
a few of the recreational activities people enjoy in
estuaries (Photo courtesy of JohnTheilgard).
National Studies ofWater
Quality
Statistically valid, probability-based studies can
complement targeted monitoring and assessment
programs and add substantially to our understanding
of state, regional, and national water quality condi-
tions, including how broad water quality conditions
may change over time. These studies select sites
at random to represent the condition of waters in
regions that share similar ecological characteristics
and are a more cost-effective approach to monitoring
than more traditional census-type or targeted
approaches.
National Water Quality Inventory: Report to Congress
ES-3
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Executive Summary
EPA and its partners have embarked on three
national probability-based studies that are discussed
later in this report: the National Coastal Assessment,
the National Study of Chemical Residues in Lake
Fish Tissue, and the Wadeable Streams Assessment.
EPA is also funding pilot projects that will provide a
foundation for a future comprehensive assessment of
the nation's lakes. National, regional, and state-wide
probability-based studies will provide much-needed
information on water quality throughout the United
States.
Future Reporting
States are working to strengthen their water
monitoring and assessment programs by developing
long-term monitoring strategies that identify the
specific actions needed to move toward more
comprehensive and consistent reporting of water
quality conditions. In addition, states and EPA
are streamlining water quality monitoring and
assessment by integrating various Clean Water Act
reporting requirements and moving toward improved
electronic reporting of water data. The results of
these efforts will be more comprehensive information
that can be easily accessed by water quality managers
and the public.
Data collected from probability-based studies and targeted monitoring efforts
can be combined to broaden our understanding of water quality conditions
(Photo courtesy ofTetraTech, Inc.).
ES-4
National Water Quality Inventory: Report to Congress
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Background
Photo courtesy of JohnTheilgard
Under Section 305(b) of the Clean Water Act,
states, territories, and other jurisdictions of the
United States are required to submit reports on the
quality of their waters to the U.S. Environmental
Protection Agency (EPA) every two years. In the
past, states submitted these reports in hardcopy
format, and EPA prepared a national hardcopy report
that summarized their findings (see http://www.
epa.gov/305b). Under Section 303(d) of the Clean
Water Act, states also biennially provide a separate
prioritized list of waters that are impaired and require
the development of pollution controls (to learn more
about Section 303 (d) reporting, visit http://www.epa.
gov/owow/tmdl).
Beginning with the 2002 reporting cycle, EPA
urged states to combine these two reporting require-
ments into one integrated report and to submit these
reports electronically. Few states submitted fully
integrated reports for the 2002 cycle, although an
increasing number are expected to do so in future
reporting cycles. This electronic information on
water quality assessment results is housed in the
2002 National Assessment Database. To increase the
usefulness of this information to the public, EPA is
presenting state-reported assessment information
(which does not include Section 303 (d) information
prioritizing impaired waters for 2002) on the Internet
at http://www.epa.gov/waters/305b.
National Water Quality Inventory: Report to Congress
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Background
About the National Assessment
Database
The 2002 National Assessment Database presents
electronic water quality information for almost all
states, the District of Columbia, and the U.S. Virgin
Islands. Three states (Alabama, North Carolina, and
Washington), Puerto Rico, the tribal nations, and the
island territories of the Pacific did not provide data
electronically in 2002. This lack of data may account,
at least in part, for the fewer number of river miles,
lake acres, and estuarine square miles reported as
assessed in 2002 compared to the previous reporting
cycle.
To view the 2002 National Assessment Database,
go to http://www.epa.gov/waters/305b and click
on the map to find summary information and
assessment results for specific states, watersheds,
and waterbodies of interest. A series of tables and
charts summarizing water quality information for the
nation as a whole, based on the 2002 state reports,
can also be viewed at this Web site.
One of the goals of the Clean Water Act
is "to restore and maintain the chemical,
physical, and biological integrity of the
nation's waters."
The information contained in the National
Assessment Database is useful for the snapshot view
it provides of waters assessed by the states during
the 2002 reporting cycle. The database collects
the findings of 49 state and territory water quality
monitoring programs for 2000-2002; lists which
pollutants and pollution sources affected individual
waters, watersheds, and states; and reports which
waters met the uses for which they were designated.
This state data can be viewed through the National
Assessment Database's interactive mapping tool,
which displays a wide range of environmental
information.
Integrated Water Quality Reporting
EPA has encouraged states to combine biennial
state water quality reporting requirements under
Sections 305(b) and 303(d) of the Clean Water Act
for several reasons. Integrating these reports will
merge environmental data from a variety of water
quality programs and will benefit the public by
providing a more informed summary of the quality
of state waters. It will also provide decision makers
with better information on the actions necessary
to protect and restore these waterbodies. The
integrated report will also streamline state reporting
requirements by eliminating the need for two
separate reports.
In the 2004 cycle, EPA expects to see state
progress toward integration of Sections 305(b)
and 303(d) water quality reporting, although full
integration may not occur until 2006 or beyond. To
facilitate the states' efforts to improve integrated
reporting, EPA published new integrated reporting
guidance in August 2005. For information on the
current status of 303(d) lists of impaired waters and
integrated reporting, go to http://www.epa.gov/
owow/tmdl.
National Water Quality Inventory: Report to Congress
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Background
Comparability of Water Quality Data
Although the information in the National
Assessment Database provides a picture of state
assessment results, these data should not be used
to compare water quality conditions between states
or to identify trends in statewide or national water
quality. The following are reasons for this lack of
comparability:
• The methods states use to monitor and assess
their waters, including what and how they
monitor and how they report their findings
to EPA, vary from state to state and within
individual states over time. To better protect
the health of their citizens, many states target
their limited monitoring resources to waters that
are suspected of being impaired or to address
local priorities and concerns; therefore, the small
percentage of waters assessed may not reflect
statewide conditions. States may monitor a
different set of waters from one reporting cycle
to another, or they may monitor fewer waters
when state budgets are limited.
• The science of monitoring and assessment
varies over time, and many states are better able
to identify problems as their monitoring and
analytical methods improve. For example, states
are conducting more fish tissue sampling than in
previous years. The use of improved assessment
methods to collect more and better information
may result in more extensive and protective
fish consumption advisories, even though water
quality conditions themselves may not have
changed.
2002 was a transition period between traditional
305(b) reporting and integrated 305(b)/303(d)
reporting. States that included 303(d)
assessment information may have relied on more
stringent rules for data acceptability than those
states without integrated reporting.
Under the Clean Water Act, each state has the
authority to set its own water quality standards;
therefore, each state's definition of its designated
uses (e.g., Warm Water Fishery or Livestock
Watering) may differ from definitions used by
other states, along with the criteria against which
states determine impairments. (See the Assessing
Water Quality section for more information.)
EPA has collected the 2002 data into a set of
national use categories defined in the National
Water Quality Standards Database at http://
www.epa.gov/wqsdatabase. These use categories
are somewhat different from those outlined in
previous national 305(b) reports.
The most efficient way to get a good under-
standing of national water quality conditions and
trends is to use probability surveys. Probability
surveys are scientifically based studies designed
to sample water quality conditions at randomly
selected sites that are statistically representative of the
nations many distinct ecological regions. EPA and its
monitoring partners have used this methodology to
develop a series of National Coastal Condition Reports
(http://www.epa.gov/nccr). These reports summarize
the findings of the National Coastal Assessment, a
probability-based study. Another probability-based
project currently underway is the National Study of
Chemical Residues in Lake Fish Tissue (http://www.
epa.gov/waterscience/fishstudy), the first national fish
contamination survey to have statistically selected
sampling sites. EPA has also conducted a probability-
based Wadeable Streams Assessment (http://www.
epa.gov/owow/streamsurvey) to determine the
biological condition of small streams in the United
States. The Wadeable Streams Assessment was
completed in 2006.
To learn more about the water quality monitoring,
assessment, and reporting practices of a specific state,
visit the state's water quality Internet site and read the
National Water Quality Inventory: Report to Congress
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Background
Reporting Results of Statewide
Probability Surveys
The 2002 National Assessment Database
contains only electronically reported waterbody-
level information from the states. A few states
conduct statewide or regional probability-based
surveys (based on statistical random sampling) to
supplement this information and to draw broad-
scale conclusions about ecologically related waters.
EPA fully supports these efforts to increase the
percentage of assessed waters. Although the
results of these state surveys are not included in
the 2002 database, future versions of the database
will incorporate the results of state probability
surveys.
more about water quality standards, visit http://www.
epa.gov/waterscience/standards.
After setting water quality standards, states assess
their waters to determine the degree to which
the standards are being met. State water quality
assessments are normally based on five broad
types of monitoring data: biological integrity,
chemical, physical, habitat, and toxicity. (Examples
of the different types of data used to determine a
state's water quality are shown in the box Types of
Monitoring Data.) Each type of monitoring data
yields an assessment that must be integrated with
other data types for an overall assessment. Depending
on the designated use, one data type may be more
informative than others for making the final
assessment.
explanatory and programmatic information included
in most reports. The National Assessment Database
contains the Web address for each state water quality
Internet site.
Assessing Water Quality
States assess the quality of their waters based on
water quality standards they develop in accordance
with the Clean Water Act. Water quality standards
may differ from state to state, but must meet
minimum requirements. EPA must approve these
standards before they become effective under the
Clean Water Act.
Water quality standards are comprised of three
elements: the designated uses assigned to waters
(e.g., recreation, public water supply, the protection
and propagation of aquatic life); the criteria or
thresholds (expressed as numeric pollutant concen-
trations or narrative requirements) that are necessary
to protect the designated uses; and the antidegrada-
tion policy intended to prevent waters from
deteriorating from their current condition. Waters
may be designated for more than one use. To learn
Water quality monitoring results are used for
a variety of purposes, including to determine if
waters are meeting a state's water quality standards
(Photo courtesy of Lynn Betts, National Resources
Conservation Service).
National Water Quality Inventory: Report to Congress
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Background
Designated Use Categories in this Report
The states have different names for the various
uses they have designated for their waters. For
example, one state might designate as Class A those
waters that are capable of supporting fish species of
commercial and recreational value (e.g., salmon and
trout), whereas another state might classify similar
waters as Cold Water Fishery waters. In order to
be consistent with EPA's Water Quality Standards
Database, the 2002 National Assessment Database
groups state-reported uses according to the
following overall categories:
• Fish, Shellfish, and Wildlife Protection and
Propagation—Is water quality good enough to
support a healthy, balanced community of aquatic
organisms
• Recreation—Can people safely swim or enjoy
other recreational activities in and on the water?
• Public Water Supply—Does the waterbody
safely supply water for drinking after standard
treatment?
• Aquatic Life Harvesting—Can people safely
eat fish caught in the waterbody?
• Agricultural—Can the waterbody be used for
irrigating fields and watering livestock?
• Industrial—Can the water be used for
industrial processes?
• Aesthetic Value—Is the waterbody
aesthetically appealing?
• Exceptional Recreational or Ecological
Significance—Does the waterbody qualify as
an outstanding natural resource or support rare
or endangered species?
You can find out which state classifications
fit under each of these categories by clicking on
the individual use category name in the National
Assessment Database.
Hundreds of organizations in the United States
conduct water quality monitoring. Monitoring
organizations include federal, state, interstate, tribal,
and local water quality agencies; research organizations
such as universities; industries and sewage and water
treatment plants; and citizen volunteer programs.
For example, EPA and the U.S. Geological Survey
(USGS) are two federal agencies that collect water
quality monitoring data. Monitoring organizations
may collect water quality data for their own purposes
or to share with government decision makers. States
evaluate and use much of these data when preparing
their water quality reports.
The states, territories, and tribes maintain
monitoring programs to support several objectives,
including assessing whether water is safe for drinking,
swimming, and fishing. States also use monitoring
data to review and revise water quality standards,
identify impaired and threatened waters under Clean
Water Act Section 303(d), develop pollutant-specific
total maximum daily loads (TMDLs), determine the
effectiveness of control programs, adjust drinking
water treatment requirements, measure progress
toward clean-water goals, and respond to citizen
complaints or events such as spills and fish kills.
National Water Quality Inventory: Report to Congress
5
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Background
Types of Monitoring Data
Biological Integrity Data—Objective
measurements of aquatic biological communities
(usually aquatic insects, fish, or algae) used to
evaluate the condition of an aquatic ecosystem.
Biological data are best used when deciding
whether waters support aquatic life uses.
Chemical Data—Measurements of key
chemical constituents in water, sediments, and
fish tissue. Examples of these constituents
include metals, oils, pesticides, and nutrients
such as nitrogen and phosphorus. Monitoring
for specific chemicals helps states assess waters
against numerical criteria, as well as identify and
trace the source of the impairment.
Physical Data—Characteristics of water, such
as temperature, flow, suspended solids, sediment,
dissolved oxygen, and pH. These physical
attributes are often useful indicators of potential
problems and can have an effect on the impacts
of pollution.
Habitat Assessments—Descriptions of
sites and surrounding land uses; condition
of streamside vegetation and banks; and
measurement of key features, such as stream
width, depth, and substrate. These assessments
are used to supplement and interpret other
kinds of data.
Toxicity Testing—Measurements of mortality
of a test population of selected organisms, such
as fathead minnows or daphnia ("water fleas").
These organisms are exposed to known dilutions
of water taken from the sampling location. The
resulting toxicity data indicate whether an
aquatic life use is being attained. These tests
can help determine whether poor water quality
results from toxins or from habitat degradation.
Habitat assessment data may include measurements of streamside vegetation and stream
width, depth, and substrate (Photo courtesy of Colin Hill,TetraTech, Inc.).
6 National Water Quality Inventory: Report to Congress
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Findings
Rivers and Streams
The 2002 National Assessment Database
summarizes river and stream designated use support
information reported by the states by overall use
support and by individual categories of uses.
Waters are rated for overall use support as follows:
• Good—if they fully support all their designated uses;
• Threatened—if they fully support all uses, but
exhibit a deteriorating trend; or
• Impaired—if they are not supporting one or more
designated uses.
Photo courtesy of Charlie Rahm, Natural Resources Conservation Service
Overall for 2002, states assessed 695,540 miles
of rivers and streams, or 19% of the nation's
approximately 3.7 million stream miles (Figure 1).
This is about 4,400 fewer stream miles than in the
previous reporting cycle. States identified 45% of the
assessed miles as being impaired, or not supporting
one or more of their designated uses. The remaining
55% of assessed miles fully supported all uses, and
of these, 4% were considered threatened (i.e., water
quality supported use, but exhibited a deteriorating
trend).
National Water Quality Inventory: Report to Congress
7
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Findings
Individual use support assessments also provide
important details about the nature of water quality
problems in rivers and streams. Table 1 shows the
top five assessed uses in rivers and streams. States
evaluated support of the Fish, Shellfish, and Wildlife
Protection and Propagation use most frequently,
assessing a total of 596,433 stream miles (or 16%
of U.S. stream miles) and reporting that 41% of
assessed stream miles were impaired for this use.
States assessed 321,750 stream miles for Recreation
uses (primary and secondary contact) and found
recreation to be impaired in 33% of these waters.
The National Assessment Database also reports
the sources and causes of impairments, but it is
important to note that the information about specific
sources and causes of impairment is incomplete.
States do not always report the pollutant or source of
pollutants affecting every impaired river and stream.
Although states may recognize that water quality
does not fully support a designated use, they may
not have adequate data in some cases to document
the specific pollutant or source responsible for the
impairment. In past national reports, unknown or
unspecified causes and sources were included only
Figure I. Water quality in assessed river and stream miles.
Total Streams
3,692,830 Miles
358,035
Miles
Assessed Streams
695,540 Miles
4% Good but
Threatened
27,750 Miles
309,755
Miles
Table I. Individual Use Support in Assessed River and Stream Miles3.
Designated Use
Assessed Percent of Total
Miles U.S. Stream Miles
of Waters Assessed
Good
Threatened
•B
Impaired
Fish, Shellfish, and Wildlife
Protection/Propagation
596,433
16%
55%
4%
41%
Recreation
321,750
9%
64%
3%
33%
Agricultural
189,332
5%
92%
7%
Aquatic Life Harvesting
186,721
5%
57%
16%
27%
Public Water Supply
150,492
4%
81%
2%
18%
"Waterbodies can have multiple designated uses, resulting in overlap of Assessed Miles.
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as footnoted material to summary statistics. For the
first time, this 2002 report includes unspecified causes
and sources in all summary statistics to more clearly
represent what states are reporting to EPA.
Table 2 shows the top reported causes of impairment
in assessed rivers and streams. According to the
states, the top causes of river and stream impairment
regardless of designated use were the following:
• Sediment or siltation, which can smother stream
beds, suffocate fish eggs and bottom-dwelling
organisms, and interfere with drinking water
treatment and recreational uses
• Pathogens (bacteria), which indicate possible fecal
contamination that may cause illness in people
• Habitat alterations, such as disruption of stream
beds and riparian areas.
Excess sediments, pathogens, and alterations to habitat
are the leading reported causes of impairment in rivers
and streams (Photo courtesy of Tim McCabe, National
Resources Conservation Service).
Table 2. Top Causes of Impairment in Assessed Rivers and Streams*
Total Streams
3,692,830 Miles
Assessed Streams
695,540 Miles
4% Good but
Threatened
27,750 Miles
Miles
Sediment/Siltation
Pathogens
Habitat Alterations
Metals
Nutrients
100,446
82,133
80,974
52,809
52,228
0 5 10 15 20 25 30 35
Percent of Impaired Stream Miles Affected
*Percents do not add up to 100% because more than one cause or source may impair a waterbody.
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More information on state-reported
causes and sources of impairment is available
from the National Assessment Database at
http://www.epa.gov/waters/305b.
States also reported other leading causes of
impairments of rivers and streams, including metals
(primarily mercury), nutrients, thermal modifications
(e.g., water heated by factories or by runoff from
paved areas), organic enrichment/low dissolved
oxygen (i.e., organic materials such as plant matter,
food processing waste, and sewage consume oxygen
when they degrade in water), and flow alterations.
Table 3 shows the top reported sources of
impairment in assessed rivers and streams. According
to the states, the top sources of river and stream
impairment included the following:
• Agricultural activities, such as crop production,
grazing, and animal feeding operations
• Unknown or unspecified sources (i.e., the states
could not identify specific sources)
• Hydrologic modifications, such as water
diversions, channelization, and streambank
destabilization.
Other leading sources of impairment in streams
included habitat alterations (e.g., loss of streamside
habitat), natural sources (e.g., floods, droughts,
and wildlife), urban runoff and storm water, and
municipal permitted discharges (e.g., sewage
treatment plants).
Table 3. Top Sources of Impairment in Assessed Rivers and Streams*.
Total Streams
3,692,830 Miles
Assessed Streams
695,540 Miles
4% Good but
Threatened
27,750 Miles
309,755
Miles
Miles
Agriculture
Unknown/Unspecified
Hydromodification
Habitat Alterations (Not Directly
Related to Hydromodification)
Natural
113,663
91,824
79,400
51,298
41,764
0 5 10 15 20 25 30 35 40
Percent of Impaired Stream Miles Affected
*Percents do not add up to 100% because more than one cause or source may impair a waterbody.
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Lakes, Ponds, and Reservoirs
The 2002 National Assessment Database
summarizes designated use support information
reported by the states for lakes, ponds, and reservoirs
by overall use support and by individual categories
of uses.
Overall, states assessed approximately 14.8 million
acres of lakes, ponds, and reservoirs (excluding the
Great Lakes), or 37% of the nation's total 40.6
million lake acres for the 2002 reporting cycle
(Figure 2). This is 2.5 million fewer acres than
were assessed in the previous reporting cycle. States
identified 47% of assessed acres as impaired, or not
supporting one or more of their designated uses (e.g.,
fishing, swimming). The remaining 53% of assessed
acres fully supported all uses, and of these, 5% were
considered threatened.
Excess nutrients, such as nitrogen and phosphorus, can
disrupt lake ecosystems by stimulating growth of algae
and aquatic weeds (Photo courtesy of Brad Ashbaugh).
Figure 2. Water quality in assessed lake acres.
Total U.S. Lakes
40.6 Million Acres
Assessed Lakes
14,831,882 Acres
5% Good but
Threatened
810,775 Miles
7,073,
Acres
6,947,901
Acres
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Findings
Individual use support assessments provide
important details about the nature of water quality
problems in lakes, ponds, and reservoirs. Table 4
shows the top five uses assessed in lakes, ponds, and
reservoirs. States assessed about 9.7 million lake
acres for support of the Fish, Shellfish, and Wildlife
Protection and Propagation use, of which 47%
were found to be impaired. Thirty-six percent of
the approximately 9.6 million lake acres assessed for
Recreation uses (e.g., swimming and boating) were
impaired. States assessed about 5.7 million acres
of lakes and reservoirs for support of the Public
Water Supply use and identified 22% as impaired.
The Aquatic Life Harvesting use (primarily fish
consumption) was assessed in approximately
4.6 million acres; of these, 48% were impaired and
11% were considered threatened (i.e., water quality
is deteriorating).
The National Assessment Database also reports
the sources and causes of impairments, but it is
important to note that the information about specific
sources and causes of impairment is incomplete.
The states do not always report the pollutant or
source of pollutants affecting every impaired lake,
pond, and reservoir. In some cases, states may
recognize that water quality does not fully support a
designated use; however, they may not have adequate
data to document the specific pollutant or source
responsible for the impairment. The states may then
simply report the cause or source of impairment as
"unknown" or "unspecified."
The states assessed 37% of the nation's total lake acres
(Photo courtesy of Jeffrey Cole).
Table 4. Individual Use Support in Assessed Lake, Pond, and Reservoir Acres2.
Designated Use
Fish, Shellfish, and Wildlife
Protection/Propagation
Recreation
Public Water Supply
Aquatic Life Harvesting
Agricultural
Assessed
Acres
9,738,351
9,564,367
5,669,057
4,562,746
2,931,970
Percent of Total
U.S. Lake Acres
24%
24%
14%
11%
7%
Percent of Waters Assessed
Good Threatened Impaired
46%
60%
75%
41%
71%
7%
4%
3%
11%
13%
47%
36%
22%
48%
16%
"Waterbodies can have multiple designated uses, resulting in overlap of Assessed Acres.
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Table 5 shows the top reported causes of
impairment in assessed lakes, ponds, and reservoirs.
According to the states, the top causes of impairment
were the following:
• Nutrients, such as phosphorus and nitrogen,
which disrupt lake ecosystems by stimulating
growth of undesirable algae and aquatic weeds
• Metals, such as mercury, which have been widely
detected in fish tissue, where they may pose a
health risk to people and animals who eat fish
• Organic enrichment/low dissolved oxygen,
which can adversely affect aquatic life and cause
foul odors.
States also reported sediment or siltation,
nuisance exotic and invasive species (e.g., non-native
plants, fish, and shellfish), toxic organics (e.g.,
polychlorinated biphenyls [PCBs]), harmful algal
blooms, salinity, and flow alterations as other leading
causes of impairment.
More information on state-reported
causes and sources of impairment is availab
from the National Assessment Database at
http://www.epa.gov/waters/305b.
Table 5. Top Causes of Impairment in Assessed Lakes, Ponds, and Reservoirs*.
Total U.S. Lakes
40.6 Million Acres
Nutrients
Metals
Organic Enrichment/
Low Dissolved Oxygen
Sediment/Siltation
Nuisance Exotic Species
0
Assessed Lakes
14,831,882 Acres
Acres
2,864,711
2,827,608
1,339,070
1,317,938
1,264,023
10
20
30
40
50
Percent of Impaired Lake Acres Affected
*Percents do not add up to 100% because more than one cause or source may impair a waterbody.
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Table 6 shows the top reported sources of
impairment in assessed lakes, ponds, and reservoirs.
According to the states, the top sources of lake
impairment included the following:
• Unknown or unspecified sources (i.e., the states
could not identify specific sources)
• Agricultural activities, such as crop production,
grazing, and irrigation
• Atmospheric deposition from both local and
long-range sources.
Other leading sources of impairment were land
application of wastes (e.g., septic systems and
landfills), hydrologic modifications (e.g., water
diversions and flow regulation), and "other" sources
(a catch-all category, including such things as out-of-
state sources and exotic species).
Table 6. Top Sources of Impairment in Assessed Lakes, Ponds, and Reservoirs*.
Total U.S. Lakes
40.6 Million Acres
Unknown/Unspecified
Agriculture
Atmospheric Deposition
Land Application/
Waste Sites
Hydromodification
Assessed Lakes
14,831,882 Acres
7,073,207
Acres
Acres
2,743,374
2,093,641
1,829,672
1,540,224
1,525,224
Percent of Impaired Lake Acres Affected
*Percents do not add up to 100% because more than one cause or source may impair a waterbody.
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Bays and Estuaries
The National Assessment Database summarizes
state-reported designated use support information
for bays and estuaries by overall use support and by
individual categories of uses.
Overall, states assessed 30,446 square miles of bays
and estuaries, or 35% of the nation's total estimated
87,370 square miles, for the 2002 reporting cycle
(Figure 3). This is 626 fewer square miles than
were assessed by the states in the previous reporting
cycle. States identified 32% of assessed square miles
as impaired, or not supporting one or more of
their designated uses (e.g., swimming, fishing, or
shellfishing). The remaining 68% of assessed square
miles were fully supporting all uses, and of these, 2%
were threatened. It should be noted that Alaska alone
accounted for 44% of assessed estuarine square miles
in the United States and 67% of those square miles
rated as fully supported all uses.
Individual use support assessments provide
important details about the nature of water quality
problems in bays and estuaries. Table 7 shows the
top three uses assessed in bays and estuaries. States
assessed 29,064 estuarine square miles for support
of the Fish, Shellfish, and Wildlife Protection and
Propagation use and found that 29% were impaired.
(Alaska alone accounted for 13,472 square miles
assessed for this use and reported 99% of these
square miles fully supported all uses.) The Aquatic
Life Harvesting use was assessed in 10,025 square
miles and found to be impaired in 29% of assessed
Figure 3. Water quality in assessed bay and estuary square miles.
Total U.S. Bays & Estuaries
87,370 Square Miles
Assessed Bays & Estuaries
30,446 Square Miles
19,916
Square Miles'"
2% Good but
Threatened
694 Square Miles
9,836
Square Miles
Table 7. Individual Use Support in Assessed Bay and Estuary Square Miles3.
Designated Use
Square Miles
Percent of Total
U.S. Estuarine
Square Miles
Percent of Waters Assessed
Good Threatened Impaired
Fish, Shellfish, and Wildlife
Protection/Propagation
Aquatic Life Harvesting
Recreation
29,064
10,025
9,290
33%
11%
11%
69%
68%
84%
3%
3%
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Findings
waters; 15% of the 9,290 square miles assessed for
Recreation uses (e.g., swimming and boating) were
reported as impaired.
The state-reported information about specific
sources and causes of impairment is incomplete.
The states do not always report the pollutant or
source of pollutants affecting every impaired bay
and estuary. In some cases, states may recognize that
water quality does not fully support a designated
use; however, they may not have adequate data to
document the specific pollutant or source responsible
for the impairment and report the cause or source as
"unknown" or "unspecified." For the first time, this
2002 report includes unknown/unspecified causes
and sources in all summary statistics to more clearly
represent what states are reporting to EPA.
More information on state-reported
causes and sources of impairment is available
from the National Assessment Database at
http://www.epa.gOv/waters/3 05 b.
Table 8 shows the top reported causes of
impairment in assessed bays and estuaries. According
to the states, the top causes of estuarine impairment
were the following:
• Metals, primarily mercury, which has been
detected in fish tissue (Alaska alone reported
2,243 estuarine square miles impaired by metals)
• Nutrients, such as nitrogen and phosphorus from
fertilizers, which can stimulate the excess growth
of algae and aquatic weeds
• Organic enrichment/low dissolved oxygen,
which can adversely affect aquatic life and cause
foul odors.
Table 8. Top Causes of Impairment in Assessed Bays and Estuaries*.
Total U.S. Bays & Estuaries
87,370 Square Miles
Metals
Nutrients
Organic Enrichment/
Low Dissolved Oxygen
Pathogens
Unknown/Unspecified
Assessed Bays & Estuaries
30,446 Square Miles
19,916
Square Miles^
2% Good but
Threatened
694 Square Miles
9,836
Square Miles
Square Miles
4,940
2,229
2,214
2,141
2,048
0 10 20 30 40 50 60
Percent of Impaired Estuarine Miles Affected
*Percents do not add up to 100% because more than one cause or source may impair a waterbody.
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Other leading causes of impairment in bays
and estuaries included pathogens, unknown or
unspecified causes (i.e., causes that could not be
identified), impacts to benthic aquatic communities,
turbidity, pesticides, and harmful algal blooms.
Table 9 shows the top reported sources of
impairment in assessed bays and estuaries. According
to the states, the top sources of estuarine impairment
included the following:
• Unknown or unspecified sources (i.e., states
could not identify specific sources)
• Industrial sources (Alaska alone reported 2,397
square miles impaired by industrial sources)
• Municipal permitted discharges (e.g., sewage
treatment facilities).
Other leading sources of impairment in bays and
estuaries were resource extraction (e.g., mining and
runoff of mine tailings), urban runoff/stormwater,
and atmospheric deposition.
Other Waters
The 2002 National Assessment Database also
contains state-reported information on conditions in
coastal shoreline waters, ocean waters, Great Lakes,
and wetlands; however, in some cases, only a small
percentage of these resources were assessed in the
2002 reporting cycle. These waters are discussed on
the following pages.
Table 9. Top Sources of Impairment in Assessed Bays and Estuaries*.
Total U.S. Bays & Estuaries
87,370 Square Miles
Unknown/Unspecified
Industrial
Municipal Permitted
Discharges
Resource Extraction
Urban-related Runoff/
Stormwater
Assessed Bays & Estuaries
X 30,446 Square Miles
2% Good but
Threatened
694 Square Miles
9,836
Square Miles
Square Miles
0 10 20 30 40 50 60
Percent of Impaired Estuarine Miles Affected
*Percents do not add up to 100% because more than one cause or source may impair a waterbody.
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Findings
Coastal Resources
Coastal resources are identified in the National
Assessment Database in two categories: coastal
shorelines (the water immediately offshore, reported
in miles) and ocean/near-coastal waters (the area of
water extending into the ocean or gulf, range not
specified, in square miles). Very few states reported
on these important resources; therefore, this
information should not be used to draw national
conclusions.
Eight of the 27 coastal states assessed 2,571 miles
of coastal shorelines, or about 4% of the nation's
total 58,618 shoreline miles. The vast majority of
assessed shoreline miles (83%) fully supported their
designated uses. In the 17% of shoreline miles not
fully supporting their uses, pathogens and metals
were the leading causes of impairment, and urban-
related runofT/stormwater, unknown/unspecified
sources, and industrial discharges were listed as top
sources of impairment.
EPA works with states, tribes, territories, and
local governments to protect coastal swimming
beaches, and monitoring of these important resources
is increasing. Under the Beaches Environmental
Assessment and Coastal Health (BEACH) Act of
2000, EPA is developing improved tools to measure,
identify, and address contaminants in recreational
waters and to better understand how these pollutants
affect people's health. EPA also awards grants to
eligible coastal and Great Lakes states, territories, and
tribes to develop and implement beach monitoring
and notification programs. For more information on
the BEACH program, visit http://www.epa.gov/
beaches.
Nearly 5,000 square miles of oceans and near-
coastal waters, or 9% of approximately 54,120 square
miles in the United States, were assessed by seven
states in 2002. Of the assessed square miles, 87%
were identified as impaired. Metals (particularly
mercury) were by far the most commonly reported
EPA is developing improved tools to measure, identify, and address contaminants in recreational waters (Photo
courtesy of JohnTheilgard).
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Findings
cause of impairment. Atmospheric deposition was
the predominant reported source of impairment in
oceans and near-coastal waters. (It is important to
note that Texas alone assessed nearly 3,879 square
miles of ocean and near-coastal waters and reported
that 100% of its assessed square miles were impaired
due to mercury from atmospheric deposition.)
Detailed information on U.S. coastal condition
trends is available in the series of National Coastal
Condition Reports, which present the findings of a
collaborative effort between the states, EPA, and
other federal agencies to characterize the condition of
100% of the nation's coastal resources. Section 3 of
this report summarizes key findings of the National
Coastal Condition Report II.
Great Lakes
The Great Lakes—Superior, Michigan, Huron,
Erie, and Ontario—are freshwater inland seas of
vast importance for water consumption, recreation,
fisheries, power, transportation, and many other uses.
Of the eight states bordering the Great Lakes, three
states (Indiana, Michigan, and New York) reported
on the condition of their Great Lakes shoreline
miles, and three states (Indiana, Michigan, and
Pennsylvania) reported on Great Lakes open waters.
Only about 520 of 5,521 total Great Lakes
shoreline miles were assessed in 2002, and of these,
91% were reported as impaired. The leading causes
of impairment included pathogens, metals, and toxic
organics. Legacy or historical pollution—primarily
contaminated sediment—was by far the leading
source of shoreline impairment reported by the
states.
Lake Superior, MN (Photo courtesy of Richard B.
Mierement, National Oceanic and Atmospheric
Administration).
The states assessed 50,866 square miles, or 84% of
the 60,546 square miles of Great Lakes open waters
in the United States. Ninety-nine percent of the
assessed square miles of Great Lakes open waters were
rated as impaired. Priority organics, metals (primarily
mercury), and pesticides were the top three causes of
impairment, and atmospheric deposition, industrial
sources, legacy or historical pollution, and agriculture
were all cited as leading sources of impairment in the
open waters of the Great Lakes.
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Wetlands
Wetlands occur where water and land come
together for a prolonged period of time; saturation
of the land with water is the dominant factor
determining soil types and the plant and animal
communities living in the soil and on the surface.
Wetlands vary widely because of regional and local
differences in soils, topography, climate, hydrology,
water chemistry, vegetation, and other factors,
including human disturbance. Included among the
many types of U.S. wetlands are marshes, bogs,
swamps, wet meadows, vernal pools, playas, pocosins,
sloughs, peat lands, prairie potholes, and fens.
Wetlands are a critically important resource due to
the many benefits they provide to humans, aquatic
life, wildlife, and the environment. Wetlands produce
great quantities of food that attract a huge variety of
animal species. They serve as nurseries and habitat for
many game and commercial fish and wildlife species,
and they help improve water quality by intercepting
surface runoff and removing, retaining, or filtering
out a broad range of substances (e.g., nutrients,
sediments, and organic wastes). By storing and slowly
releasing water, wetlands help reduce the impacts
of floods and erosion, as well as help replenish
groundwater and stream flow during dry periods.
Wetlands are also of great recreational value to bird
watchers, hunters, fishermen, and nature lovers.
Most states lack wetland-specific designated uses,
criteria, and monitoring programs, and without these
programs, cannot evaluate support of designated uses
for wetlands. Only six states provided information
on support of designated uses for 1.3 million acres of
wetlands in their 2002 reports—a tiny portion of the
nation's estimated 105 million acres. States identified
52% percent of these assessed acres as impaired.
Metals (primarily mercury), organic enrichment/low
dissolved oxygen, and sediment/siltation were the
leading causes of wetland degradation in these six
states. The sources of these and other pollutants were
mostly unspecified. Where sources were identified,
atmospheric deposition and agriculture were top
contributors to impairment.
Wetlands produce great quantities
of food that attract a huge variety
of animal species.
Wetlands vary widely because of regional and local differences in soil, topography, climate, hydrology, water chemistry,
vegetation, and other factors (Photo courtesy of Gary Kramer, National Resources Conservation Service).
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National Studies of
Water Quality
• -•-^
- ' '•*'""'
•
Photo courtesy of Paul Fusco, Natural Resources Conseration Service
State 305(b) reports provide insight into the
condition of the relatively small number of waters
that are assessed, but should not be compared to
each other and cannot be used to track trends in
water quality over time. Water quality standards and
methods vary from state to state, and monitoring and
reporting methods also change over time. Most states
monitor only a small percentage of their waters for
each reporting cycle, and many monitor in different
watersheds from one cycle to the next. Thus, as noted
earlier in this report, 2002 state 305(b) assessment
data exists for only 19% of the nation's stream miles,
37% of lake and reservoir acres, and 35% of bay
and estuary square miles. Furthermore, as states
improve their abilities to monitor—for example,
as they analyze more fish tissue samples or monitor
the quality of more beaches—they may discover
problems that were previously unidentified.
EPA, other federal agencies, and the states have
embarked on a more cost-effective approach to
track trends in the quality of the nation's waters:
statistically valid, probability-based studies that
complement existing monitoring and assessment
programs and add to our understanding of national,
regional, and local water quality conditions.
Probability-based studies select a specific number
of sites at random to represent the condition of
waters in regions that share similar ecological
characteristics. Scientists can then draw inferences for
100% of waters with a known degree of confidence.
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21
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National Studies of Water Quality
Probability-based studies are generally characterized
by standard sampling methodologies, a defined set of
relevant indicators, and stringent quality assurance
(QA) requirements. Three of these studies, and one
study that is still in the planning stages, are discussed
over the following pages. These study results should
not be compared to the 305(b) report findings
because they address the entire resource (e.g., all U.S.
streams, coastal waters).
National Coastal Assessment
The National Coastal Assessment surveys the
condition of the nation's coastal resources, as well as
state efforts to protect, manage, and restore coastal
ecosystems. The results of these surveys are compiled
periodically into a National Coastal Condition Report.
The states, EPA, and partner agencies-—the National
Oceanic and Atmospheric Administration (NOAA),
USGS, and the U.S. Fish and Wildlife Service
(FWS)—issued the National Coastal Condition
Report II in January 2005 as the second in this series
Understanding the Value of Statistical Surveys
and the National 305(b) Report
Although some of the findings of the national
305(b) report appear similar to the findings of the
statistically based coastal and streams surveys, there
are many differences in the scope of these reports
and how they are best used to inform water quality
management.
The statistical surveys provide consistent
environmental indicators of the condition of
the nation's water resources, much as economic
indicators report on the health of the nation's
economy. Their design ensures that results represent
the population of all waters of a certain type across
the United States, and their consistent sampling
methods ensure that results can be aggregated
into regional and national indicators of the health
of the resource. The survey results quantify, with
documented confidence, how widespread water
quality problems are across the country and estimate
the extent of waters affected by key stressors. This
helps set priorities for water resource protection
and restoration. Nationally consistent surveys
provide a standardized measure for tracking changes
in the condition of the nation's waters over time
and for evaluating, at a broad scale, progress in
investments to protect and restore water quality.
In contrast to the statistical surveys, the national
305(b) report summarizes information reported by
states for only a portion of waters (approximately
19% of U.S. river and stream miles and 35% of bay
and estuarine square miles). Although an increasing
number of states are adopting statistical survey
designs to represent the condition of all state waters,
most still select monitoring sites to meet specific
needs, such as the evaluating potential downstream
impacts of permitted discharges. The national 305(b)
report tallies state findings based on data collected
using a variety of sampling methods and parameters,
water quality standards and interpretation methods,
extrapolation methods, and time periods. The 305(b)
report provides useful information on the nature of
water quality problems identified by state monitoring
programs; documents the amount of waters assessed
and unassessed; supports the identification of specific
waters not meeting water quality standards; and
thereby helps states set priorities for these waters.
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National Studies of Water Quality
National Coastal
Condition Report II
of environmental surveys of U.S. coastal waters. This
report includes evaluations of 100% of the nation's
estuaries in the contiguous 48 states and Puerto
Rico. Federal, state, and local agencies collected
more than 50,000 samples between 1997 and 2000
for the report, using nationally consistent methods
and a probability-based design to assess five key
indicators of coastal water health. These indicators
included water quality, coastal habitat loss, sediment
quality, benthic community condition, and fish tissue
contaminants.
The National Coastal Condition Report II finds
that the quality of U.S. coastal waters is generally
fair—essentially the same finding as the first National
Coastal Condition Report, which was published in
2001. Nationally, 35% of coastal resources are in
poor condition, 21% are in good condition, and
44% are threatened (fair condition) for aquatic life
use or human use. Overall confidence in the accuracy
of the data varies by indicator and region and is
about 95% nationally. Other key findings of the
report include the following:
• A fish tissue contaminants index was used to
determine the suitability of waters for fishing.
Twenty-two percent of coastal waters are impaired
for fishing, based on EPA's guidelines for
moderate consumption of recreationally caught
fish.
Twenty-two percent of coastal waters are impaired
for fishing based on the findings of the National Coastal
Condition Report II (Photo courtesy of JohnTheilgard).
National Water Quality Inventory: Report to Congress 23
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National Studies of Water Quality
Water quality, sediment quality, habitat loss,
and benthic indices were used to determine the
suitability of waters for aquatic life use. Twenty-
eight percent of coastal waters are impaired for
aquatic life use.
Among the key indicators, coastal habitat
condition, sediment quality, and benthic condition
ranked the lowest. Individual components of water
quality, including dissolved oxygen and dissolved
inorganic nitrogen, ranked slightly better.
From a regional perspective, the coastal condition
in the Southeast is rated as good, the Gulf of
Mexico and the West are rated as fair, the Great
Lakes are rated as fair to poor, and the Northeast
and Puerto Rico are rated as poor. Figure 4
summarizes these ratings.
The National Coastal Condition Report II presents
a broad baseline picture of the condition of estuaries
across the United States from 1997-2000 and will
serve as a benchmark for analyzing the progress of
coastal programs in future years. A third report is
expected in 2008 and will assess regional trends
for the majority of the United States. To view the
National Coastal Condition Report II, go to http://
www.epa.gov/nccr.
)verall National
Coastal Condition
Overall
Great Lakes
Overall
Northeast
Fair Poor
Overall
West
Ecological Health
Water Quality Index
Sediment Quality Index
Benthic Index
Overall
Gulf
Overall
Puerto Rico
Coastal Habitat Index
Fish Tissue Index
Surveys completed, but no indicator
data available until the next report.
Surveys completed, but no indicator
data available until the next report.
Figure 4. Summary of the overall national coastal condition (U.S. EPA/NCA).
24
National Water Quality Inventory: Report to Congress
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National Studies ofWater Quality
National Study of Chemical
Residues in Lake Fish Tissue
The National Study of Chemical Residues in
Lake Fish Tissue (or the National Lake Fish Tissue
Study) is nearing completion. This study includes
the largest set of chemicals studied in fish and is
the first national fish contamination survey to
have sampling sites that were statistically selected.
Agencies in 47 states, 3 tribes, and 2 other federal
agencies collaborated with EPA for 4 years to collect
fish from 500 lakes and reservoirs in the lower 48
states. Sampling teams applied consistent methods
nationwide to collect samples of predator and
bottom-dwelling species from each lake.
EPA is analyzing fish tissue samples for 268
chemicals, including mercury, arsenic, dioxins
and furans, PCBs, and pesticides. A draft report is
expected in the fall of 2007. This study will provide
the first national estimates of mean concentrations of
the 268 target chemicals in fish, as well as a national
baseline to track the progress of pollution-control
activities that limit release of these chemicals into the
environment. For more information on the National
Lake Fish Tissue Study, go to http://www.epa.gov/
waterscience/fishstudy.
The National Lake Fish Tissue Study is analyzing fish
tissue samples for 268 chemicals (Photo courtesy of
EPA).
Wadeable Streams Assessment
The Wadeable Streams Assessment, a survey of the
biological health of the nation's wadeable streams,
was launched in 2004 by EPA and the states to
provide a scientific baseline of stream water quality
based on conditions at approximately 500 randomly
selected sites across the central and eastern United
States. With support from EPA, state water quality
agencies sampled streams between June and October
2004 using the same types of methods at all sites.
Crews collected macroinvertebrates, sampled water
quality conditions, and evaluated physical habitat
(i.e., the condition of the streambed, streambanks,
and vegetation surrounding the stream site) at each
site. Data from these sites were combined with data
collected by EPA and western states in the Western
Streams Pilot Study to draw conclusions about the
condition of 100% of streams throughout each major
ecological region of the contiguous United States
(Figure 5).
National Water Quality Inventory: Report to Congress
25
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National Studies ofWater Quality
Figure 5. Wadeable Streams Assessment sampling sites (U.S. EPA/WSA).
TheWadeable Streams Assessment collected data at 1,392 wadeable, perennial stream locations, such as this one in
Sawmill Creek, MA, in the Northern Appalachians ecoregion (Photo courtesy of Colin Hill.Tetra Tech, Inc.).
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National Water Quality Inventory: Report to Congress
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National Studies ofWater Quality
Key Findings of the Wadeable Streams Assessment
The Wadeable Streams Assessment found that
42% of U.S. stream miles are in poor condition
compared to best-available reference sites in their
ecological regions, 25% are in fair condition, and
28% are in good condition (Figure 6). The
confidence level for these key findings of biological
quality is + or -2.8%. Five percent of U.S. stream
miles were not assessed.
Three major regions were outlined for this
assessment: the Eastern Highlands, the Plains and
Lowlands, and the West. Of these three groups,
the West is in the best condition, with 45% of the
length of wadeable, flowing waters in good condition.
The Eastern Highlands region presents the most
concerns, with only 18% of the length of wadeable
streams and rivers in good condition and 52% in
poor condition.
,1.7%
The study also found that the most widespread
stressors observed across the country and in each
of the three major regions are nitrogen, phosphorus,
riparian disturbance, and streambed sediments.
Increases in nutrients and streambed sediments have
the highest impact on biological condition; streams
scoring poor for these stressors are twice as likely
to have poor biological condition as streams that
score in the good range for the same stressors.
Future updates of this study will include work
currently being conducted in Alaska, Hawaii, and
Guam. The study will be repeated in future years to
track national trends in stream condition. For more
information on the assessment, go to http://www.
epa.gov/owow/streamsurvey.
,2.0%
9.5%
West
152,425 miles
Plains and Lowlands
242,264 miles
Eastern Highlands
276,362 miles
National
Biological Condition
5.0%
• Good
D Fair
• Poor
D Not Assessed
WSA
Major Regions*
CD West
OS Plains and Lowlands
wm Eastern Highlands
"based on Omernik
Level III ecoregions
Figure 6. Biological condition of wadeable streams (U.S. EPA/WSA).
National Water Quality Inventory: Report to Congress 27
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National Studies of Water Quality
Assessing Lakes
EPA and the states are currently making
preparations for a comprehensive assessment of the
nation's lakes that will serve as a baseline of lake
water quality against which future trends can be
tracked. EPA has awarded National Lakes Assessment
Planning Project grants to study which sampling
designs, indicators, collection methods, and data-
interpretation methods would best suit the many
types and sizes of lakes and reservoirs in the United
States. A national meeting was held in the spring of
2006 to share findings and to develop a consensus
approach to a national assessment of lake water
quality.
Through the institution of regular probability
surveys of all waterbody types, EPA and its
partners in the states and other federal agencies
will be able to cost-effectively assess 100% of
the water resources of the United States and
track trends in water quality over time. This
scientifically based data will assist in the evaluation
of the effectiveness of pollution-control activities
and will greatly improve our ability to manage the
nation's water resources.
A total of 909 lakes, ponds, and reservoirs in the contiguous United States are included in the National Lakes
Assessment Survey of the Nation's Lakes (Photo courtesy of Gene Alexander, National Resources Conservation
Service).
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National Water Quality Inventory: Report to Congress
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Future Reporting
«v
••••• mmmmm^m •^^^•••••••••••B
Photo courtesy of Lauren Holbrook, IAN Image Library
For many years, water quality monitoring,
assessment, and reporting in the United States has
suffered from inconsistencies in state programs and
methods, as well as the lack of scientifically defensible,
national-level information that could be used to track
water quality changes over time. The probability-based
studies mentioned above are designed to address the
need for national-level information.
Improving state water monitoring and assessment
programs is an ongoing effort. EPA issued guidance
in March 2003 describing basic elements of a state
monitoring and assessment program (e.g., monitoring
objectives, monitoring designs, core water quality
indicators, a quality assurance program, a data
management system, data analysis methodologies,
reports on findings, periodic program evaluation,
identification of future needs, and a long-term
strategy to implement these elements). In response to
this guidance, states have prepared comprehensive,
long-term strategies that address all water types,
including those for which little data currently exist.
These strategies will help identify needed actions
and overall challenges facing states as they work to
improve monitoring over the coming decade.
The states and EPA are taking steps toward
streamlining and improving water quality monitoring
and assessment by integrating monitoring and
reporting requirements under Sections 30 5 (b) and
National Water Quality Inventory: Report to Congress
29
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Future Reporting
303(d) of the Clean Water Act. Section 305(b)
requires states to report biennially on the condition
of their waters. Under Section 303(d), states,
territories, and authorized tribes are required to
develop lists of impaired waters. Impaired waters
are those waters that do not meet water quality
standards, even after point sources of pollution have
installed the required levels of pollution-control
technology. The Clean Water Act requires that these
jurisdictions establish priority rankings for waters on
the lists and develop TMDLs for these waters.
ATMDL specifies the maximum amount
of a pollutant that a waterbody can receive
and still meet water quality standards; it also
allocates pollutant loadings among point and
nonpoint pollutant sources.
EPA has issued guidance to the states to clarify
integrated reporting requirements for the 2006
reporting cycle and has established a goal that all
50 states and 6 territories and jurisdictions use
the integrated reporting format by 2008. EPA
continues to promote this comprehensive assessment
approach to improve the states' ability to track
both the programmatic and environmental goals
of the Clean Water Act, and ideally, to increase the
pace of achieving these important environmental
goals. (See http://www.epa.gov/owow/tmdl for
more information on EPA's national water quality
reporting guidance.)
For the 2002 305(b) cycle, states were asked to
submit their monitoring findings electronically using
EPA's Assessment Database, a tool developed for state
reporting. Most provided electronic data in alternate
yet compatible formats, and EPA transferred these
data into the National Assessment Database for
purposes of national reporting. This electronic
reporting requires a significant commitment at the
state and national levels. EPA and the states are
working to ensure that each assessed watershed and
waterbody is identified using a consistent national
surface water locational system (the National
Hydrography Dataset). States enter their assessment
results (e.g., whether a waterbody is supporting
its designated uses, which uses are not supported,
and what is causing impairment) for each sampling
location. EPA will continually adapt and improve
the National Assessment Database to reflect new
reporting requirements and the full range of state
monitoring activities (including probability-based
surveys), as well as continue to fully support
state efforts to adopt electronic reporting. This
commitment will yield more comprehensive
information that can be easily accessed by water
quality managers and the public.
As this report has shown, we are limited by our
lack of complete knowledge about many of the
nation's waters. Without this knowledge, we cannot
accurately determine how effective our pollution-
control programs are or if water quality conditions
are improving or declining. Monitoring strategies,
integrated reporting, and electronic reporting of
assessment findings, along with probability-based
national and regional studies, are all designed to
improve what we know about the nation's water
quality conditions. EPA and the states are committed
to working toward providing better methods for
water quality monitoring and assessment and
improved data in the future.
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National Water Quality Inventory: Report to Congress
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