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A Profile from the 2000 National Water Quality Inventory
In 2000, states, tribes, territories, and interstate commissions report that about 40% of streams,
45% of lakes, and 50% of estuaries that were assessed were not clean enough to support uses such as
fishing and swimming (Figure 1). About 33% of U.S. waters were assessed for this national inventory
of water quality. Leading causes of impairment in assessed waters include bacteria, nutrients, metals
(primarily mercury), and siltation (Figure 2). Runoff from agricultural lands, municipal point sources
(sewage treatment plants), and hydrologic modifications (such as channelization, flow regulation, and
dredging) are the primary sources of impairment. Although the United States has made significant
progress in cleaning up polluted waters over the past 30 years, much remains to be done to restore
and protect the nation's waters.
Background
This fact sheet summarizes the findings of the National
Water Quality Inventory: 2000 Report, prepared under
Section 305(b) of the Clean Water Act. Section 305(b)
requires that states, territories, and jurisdictions assess
their water quality biennially and report those findings
to the U.S. Environmental Protection Agency (EPA).
EPA then summarizes the findings in a national water
quality inventory. It is important to note that this
report is no longer a Report to Congress, pursuant to
Public Law 104-66, the Federal Reports Elimination
and Sunset Act of 1995.
To assess water quality, states and other jurisdictions
compare their monitoring results to the water quality
standards they have set for their waters. Water quality
standards consist of three elements: the designated
uses assigned to waters (such as drinking, swimming,
or fishing), criteria to protect those uses (such as
chemical-specific thresholds that should not be
exceeded), and an antidegradation policy intended to
keep waters that do meet standards from deteriorating
from their current condition.
Findings
In their 2000 reports, states, tribes, territories, and
other jurisdictions assessed approximately 700,000
miles of rivers and 17.34 million acres of lakes, slightly
less area than in their 1998 reports. This decrease is
largely due to the states' growing reluctance to use
older qualitative data when making water quality
assessments. More often, states are choosing to use
only high quality monitoring data for the purpose of
these assessments. States assessed about 31,000
square miles of estuaries, slightly more than in the last
reporting cycle. Figures 1 and 2 summarize the quality
of assessed river miles, lake acres, and estuary square
miles.
In 2000, mercury was described as a leading cause of
impairment in the nation's estuaries and lakes. Increas-
ingly, states are moving toward more comprehensive
Figure 1. Summary of Quality of Assessed Rivers, Lakes, and Estuaries
Waterbody Type
~H. <*^^
Rivers
(miles)
r*~i Łt>
\\ l'fťW
_~v. -,
Estuaries
(sq. miles)
Total
Size
3,692,830
40,603,893
87,369
Amount
Assessed*
(% of Total)
699,946
(1 9%)
17,339,080
(43%)
31,072
(36%)
Good
(% of Assessed)
367,129
(53%)
8,026,988
(47%)
1 3,850
(45%)
Good but
Threatened
(% of Assessed)
59,504
(8%)
1,348,903
(8%)
1,023
(<4%)
Polluted
(% of Assessed)
269,258
(39%)
7,702,370
(45%)
15,676
(51%)
includes waterbodies assessed as not attainable for one or more uses.
Note: percentages may not add up to 100% due to rounding.
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Figure 2. Leading Causes and Sources* of Impairment in Assessed Rivers, Lakes, and Estuaries
Causes
Sources
Rivers and Streams
Pathogens (Bacteria)
Siltation (Sedimentation)
Habitat Alterations
Agriculture
Hydrologic Modifications
Habitat Modifications
Lakes, Ponds, and Reservoirs
Nutrients
Metals (Primarily mercury)
Siltation (Sedimentation)
Agriculture
Hydrologic Modifications
Urban Runoff/Storm Sewers
Estuaries
Metals (Primarily mercury)
Pesticides
Oxygen-Depleting Substances
Municipal Point Sources
Urban Runoff/Storm Sewers
Industrial Discharges
*Excluding unknown, natural, and "other" sources.
examination of fish tissue and are issuing statewide
advisories that restrict the consumption of some fish,
especially for vulnerable segments of the population.
Mercury, which originates from air transport from
power-generating facilities and incinerators, mining,
natural rock weathering, and other sources, was cited
in 2,242 of the 2,838 fishing advisories reported by the
states in 2000.
In addition, the states, tribes, territories, and jurisdic-
tions assessed the quality of ocean and Great Lakes
shoreline miles, wetlands, and ground water.
Of the assessed ocean shoreline miles, 14% are
impaired, primarily because of bacteria, oxygen
depletion, and turbidity. Primary sources of pollution
include urban runoff, storm sewers, nonpoint source
runoff, and land disposal of wastes. States assessed
only 6% of the nation's ocean shoreline miles.
States also found that 78% of assessed Great Lakes
shoreline miles are impaired, primarily due to pollut-
ants in fish tissue at levels that exceed standards to
protect human health. States assessed 92% of Great
Lakes shoreline miles.
The average annual loss of wetlands has decreased
over the past 40 years to a current estimated loss of
58,500 acres per year. Nine states and tribes listed
sources of recent wetland loss. Leading reasons for
loss are filling and draining, conversion for agricul-
tural uses, residential development, and road con-
struction.
Overall, the states found that ground water quality
is good and can support many different uses.
However, measurable negative impacts have been
detected in some areas and are commonly traced
back to sources such as leaking underground
storage tanks, septic systems, and landfills.
Future Reporting
In an effort to improve the consistency and compre-
hensiveness of water quality reporting and to stream-
line the reporting process, EPA is providing states,
territories, and tribes with guidance that recommends
they submit a 2002 Integrated Water Quality Monitor-
ing and Assessment Report to satisfy the requirements
for both Sections 305(b) and 303(d) of the Clean
Water Act (Section 303(d) requires states to identify
impaired waters and develop allocations of the maxi-
mum amount of a pollutant each impaired water can
receive and still meet water quality standards). The
guidance is available at http://www.epa.gov/owow/
tmdl/2002wqma.html. EPA anticipates that the devel-
opment of an Integrated Report will benefit the public
by providing a clearer summary of the water quality
status of the nation's waters and the management
actions necessary to protect and restore them. The
Integrated Report will also enhance the ability of water
quality managers to display, access, and integrate
environmental data and information from all com-
ponents of the water quality program.
For Further Information
For a copy of the National Water Quality Inventory:
2000 Report (EPA-841-R-02-001), visit www.epa.goy/305fo
or call the EPA's National Service Center for Environ-
mental Publications at 1-800-490-9198.
United States Environmental Protection Agency
Office of Water (4503F)
EPA-841 -F-02-003 August 2002
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