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Importance of the National Watershed Characterization
The Index of Watershed Indicators characterizes the condition and
vulnerability of aquatic systems in each of the 2,111 watersheds in the
continental U.S. This involves an assessment of condition, vulnerability,
and data sufficiency.
The approach is simple. First, indicators of the condition of the watershed
are scored and assigned to one of three categories: better water quality, water
quality with less serious problems, and water quality with more serious
problems. Second, indicators of vulnerability are scored to create two
characterizations of vulnerability: high and low. These two sets of indicators
are then combined to create the following spectrum:
1. Watersheds with better water quality and lower vulnerability to stressors
such as pollutant loadings
2. Watersheds with better water quality and higher vulnerability to stressors
such as pollutant loadings
3. Watersheds with less serious water quality problems and lower
vulnerability to stressors such as pollutant loadings
4. Watersheds with less serious water quality problems and higher
vulnerability to stressors such as pollutant loadings
5. Watersheds with more serious water quality problems and lower
vulnerability to stressors such as pollutant loadings
6. Watersheds with more serious water quality problems and higher
vulnerability to stressors such as pollutant loadings
7. Watersheds for which insufficient data exists to make an assertion of
condition or vulnerability
The Index of Watershed Indicators shows that about:
• 16% of the watersheds in the country have better water quality and of
these, one in eight have high vulnerability;
• 36% have some water quality problems and of these, about one in ten these
high vulnerability;
» 21% have more serious water quality problems with one in ten of these
exhibiting high vulnerability; and,
• 27% of the watersheds in the continental United States do not have enough
information on the component indicators to make an overall assessment.
The information provided by the Index of Watershed Indicators will help focus
the attention of water quality managers and decision makers on areas with
problems in need of restoration, on areas with good water quality in need of
protection, and on areas where additional data is needed. When looking at the
results of the IWI, however, it is important to note that the strength of monitoring
programs varies across the country. Areas with strong monitoring programs may
show more problems than those with weaker programs. Good monitoring
provides valuable environmental information and should be rewarded.
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your Watershed" at:
Click on the data layer of interest to find
documentation and FTP (File Transfer Protocol) addresses.
Data Sufficiency Thresholds
Data sufficiency thresholds levels were set for data in both the condition and
vulnerability categories. These threshold levels ensure that sufficient data
exists to make a valid judgement of aquatic resource health. For the
condition data layers, each watershed must have information for at least four
out of seven data sets or they are are considered to have "Insufficient Data."
A similar data sufficiency screen is applied to vulnerability data, where at
least six of the eight indicators are needed.
Notes on Interpreting this Information
• This map combines 15 disparate data layers as listed above. All of the notes
listed for the component data layers must be taken into account when using
this map.
» State water quality assessments (305(b) designated use data) were given
special consideration. First, when State 305(b) data were present, this data
layer was weighted six times more heavily than other data layers. Wliere they
were absent, the data from other condition indicators were weighted more
heavily to compensate for this missing information
Plans to Improve this Data Layer
As the data for each of the component data layers is improved, the overall Index
of Watershed Indicators map will also improve. U.S. EPA will continue to work
on revising the scoring system to ensure it reflects aquatic resource condition and
vulnerability as accurately as possible.
For More Information Contact:
Individual Contact
Charles Spooner, 202 260-1314
E-mail: Spooner.Charles@epamail.epa.gov
Page 7
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1. Assessed Rivers Meeting All Designated Uses
Set in State/Tribal Water Quality Standards
1994/1996
Analysis of Alaska and
I la\\a i reserved tor Phase 2
Percent of Assessed Watershed Rivers
Meeting All Designated Uses:
I I 80 -100% Meeting All Uses
| | 50 - 79% Meeting All Uses
| [ 20 - 49% Meeting All Uses
JH| < 20% Meeting All Uses
H H Insufficient IWI Data
Index of Watershed
Indicators
Sources: U.S. Environmental Protection Agency
National Water Quality Invert ory
June 27. 1 597
n 4.93.1*13!
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Map 1
Importance of Assessed Rivers Meeting All Designated
Uses Set in State/Tribal Water Quality Standards
States and Tribes adopt water quality standards that include designated uses and
criteria to protect those uses. Uses typically include drinking water supplies,
aquatic life use support, fish and shellfish consumption, primary and secondary
contact recreation (e.g., swimming and boating), and agriculture. States and
Tribes describe water quality in terms of a waterbody either fully supporting,
partially supporting, or not supporting the designated use and report this
information biennially to U.S. EPA which then compiles it in the National
Water Quality Inventory Report to Congress (305(b)) Report.
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your Watershed"
at:
. Click on the data layer of interest to find
documentation and FTP (File Transfer Protocol) addresses.
Data Sufficiency Thresholds
State and Tribal assessments were considered sufficient to characterize the
condition of a watershed if more than 20% of the total perennial stream miles
(as expressed by Reach File 3 (RF3)) were assessed. RF3 is a computer
database showing the location and flow direction of surface waters compiled
from maps produced by the U.S. Geological Survey. 20% approximates the
lower 25th percentile of assessed watershed miles for the entire country. Since
RF3 total water estimates are not available for U.S. EPA Region 10 States (AK,
ID, OR, WA), all watershed data were retained for these watersheds. Section
305(b) data from the Delaware River Basin Commission and the Ohio River
Valley Sanitation Commission were used to complement State coverage of those
two rivers without applying the 20% test.
Notes on Interpreting this Information:
• Data Somewhat Consistent/Additional Data Needed
Nationally, additional data are needed in many places. Reported data
are based on National guidelines issued from U.S. EPA, but may vary
from place to place due to different water quality standards and
methods. See "Plans to Update this Data Layer" for details.
• States and Tribes do not have identical water quality standards or
identical methods or criteria to assess their waters so data may not be
consistent.
• Most States and Tribes cannot assess all of their waters during each
two-year reporting period, and they may modify techniques used or
assess different waters every two years.
• Most monitoring undertaken by States and Tribes is focused on rivers.
lakes and estuaries with suspected or identified pollution problems
Assessments based on this type of monitoring may not be representative
of the whole watershed and may overestimate the degree of concern.
Plans to Improve this Data Layer
U.S. EPA has several initiatives underway to improve the quality of the 305(b)
data,
• U.S. EPA is working with States, Tribes, other federal agencies, and
other partners to develop monitoring and assessment approaches that
will improve state-to-state consistency in reporting.
• U.S. EPA is also working with its partners to achieve comprehensive
coverage of the waters in the nation in the 305(b) report, and include
annual electronic updates of key data elements.
• This indicator will be updated using the 1996 and subsequent database
updates as they become available.
For More Information Contact:
Database Owner:
US. EPA, Office of Wetlands, Ocean and Watersheds
Individual Contact:
Charles Spooner
E-mail: Spooner.Charles@epamail.epa.gov
Phone: (202)260-1314
Data Source:
1. National Water Quality Inventory: 1994 Report to Congress
U.S. Environmental Protection Agency, Office of Water Washington,
D.C. December 1995. EPA 841-R-95-005,
2. National Assessment Database
U.S. Environmental Protection Agency, Office of Water, 1994
Waterbody System Data
State of Georgia, 1996
Additional Information
For more information on specific State 305(b) reports contact U S, EPA's Barry
Burgan at Burgan.Barry@epamail.epa.gov or (202) 260-7060
Page 9
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2. Fish and Wildlife Consumption Advisories
1995
VVJ
Analysis of Alaska and
Hawaii reserved for Ptese 2
Watershed Classification
[ ] Monitored with No Active Advisory
j I One or More Advisories Recommending Limits on Fish Consumption
| | One or More Advisories Recommending No Fish Consumption
I I No Recorded Monitoring and No Advisories
Index of Watershed
Indicators
Souices U.S. Emiroumental Protection Agency
l Listing of Fish & Wildlife
.lune VI 1 9)7
-------
Map 2
Importance of Fish and Wildlife Consumption Advisories
Fish consumption advisories are a good indicator of the condition of a
watershed because they can represent bioaccumulation of toxic substances
in fish and shellfish. Bioaccumulation is the process by which fish
accumulate pollutants in their tissues by eating smaller organisms already
contaminated with the pollutant. Pollutants can also enter fish and shellfish
tissue directly from the surrounding water through their gills and skin.
These pollutants cause fish and shellfish to be unsafe for human
consumption.
States monitor fish to determine whether levels of contamination in fish
tissue pose a threat to the health of the people who eat them. Where fish
contamination levels exceed safe levels, States often issue advisories to the
public recommending some limitation on fish consumption (generally
restrictions on the number of meals over a period of time or the fish weight
consumed over a period of time) or no consumption offish at all.
Advisories may also target a specific subpopulation at risk such as children,
pregnant women, and nursing mothers.
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your
Watershed" at: . Click on the data
layer of interest to find documentation and FTP (File Transfer Protocol)
addresses.
You can also access the National Listing of Fish & Wildlife Consumption
Advisories database on at http://www.epa.gov/OST/fishadvice/
Data Sufficiency Thresholds
One smaller waterbody under a fish consumption advisory in a watershed is
sufficient to characterize the entire watershed in this analysis. Similarly,
data showing that monitoring has occurred and the determination has been
made that an advisory is not appropriate is sufficient to characterize a
watershed.
Notes on Interpreting this Information
• Data Somewhat Consistent/Additional Data Needed
See "Plans to Improve this Data Layer" for details.
* Characterizations for cross-boundary watersheds may be made
due to advisories in only one of the involved States or Tribes,
regardless of the amount of area covered by that State or Tribe.
• Fish consumption advisories are issued by State, Tribal, local, and
federal governments and each uses its own criteria for determining
when an advisory is warranted. In addressing these risks,
advisories may reflect data from many or a few sites, may vary in
the number and types of contaminants considered, may apply to
only certain types ofwaterbodies, and may apply to only certain
species or sizes offish.
• Monitoring for fish tissue contamination may be concentrated in
areas of most intense fishing or areas suspected of contamination.
• For the purposes of this characterization nonconsumption
advisories include those issued for the general public and/or for
special sub-populations (e.g. pregnant women).
Plans to Improve this Data Layer
This indicator will be updated using 1996 data and subsequent database updates as
they become available. EPA is looking at other sources of data, such as
contaminants in fish tissue, that may more accurately reflect bioaccumulation of
toxic substances in fish and shellfish.
For More Information Contact:
Database Owner:
U.S. EPA Office of Science and Technology
Individual Contact
Jeff Bigler
E-mail: Bigler. Jeff@epamail. epa. gov
Phone: 202-260-1305
Data Source:
National Listing of Fish & Wildlife Consumption Advisories, 1995
U.S. Environmental Protection Agency, Office of Science and
Technology
Page
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3. Indicators of Source Water Condition
for Drinking Water Systems
1990 -1996
Analysis of Alaska ard
Hawaii reserved for Phase 2
Includes Ground and Surface Water Sources
Watershed Classification
| | No Significant Source Water Impairment Identified
| | Partial Source Water Impairment Identified
f~| Significant Source Water Impairment Identified
~—| Data Sufficiency Threshold Not Met
Index of Watershed
Indicators
Source: U.S. Environmental Protection Agency
June 24, ]
-------
Map 3
Importance of the Indicators of Source Water Condition for
Drinking Water Systems
The availability of clean and safe drinking water sources for use by drinking water
systems is a good indicator of the watershed's condition. Water systems are major users
of the water resources and have continual interest in the quantity and quality of their
water supplies. Impaired source waters prompt corrective actions (including additional
treatment) by water systems to ensure that the water provided at the tap to consumers
meets all drinking water standards.
Data to characterize the quality of these source waters is not available nationally. No
single data source currently exists to provide an accurate and complete picture of source
water condition. However, using surrogate measures from different data sets can provide
a partial picture of the source water condition. This data layer combines three indicators
to identify if there is evidence in the watershed of: (1) no significant source water
impairment, (2) partial source water impairment, or (3) significant source water
impairment in the watershed.
The three indicators used to characterize source water condition were a) rivers and lakes
supporting state drinking water designated uses, b) two Safe Drinking Water Information
System (SDWIS) surrogate indicators of source water condition; and, c) the occurrence
of chemicals regulated under the Safe Drinking Water Act in ambient waters
Although not displayed here, indicators of source water vulnerability provide additional
evidence of the risk to the use of source waters by water systems. Looking at current
source water condition alone provides only a partial picture of source water. Other data
layers may provide an indication of the vulnerability to source waters. See Map 12,
Index of Agricultural Runoff Potential, for example.
A combined map of source water condition and vulnerability that will include other
indicators of condition and vulnerability will be developed for future phases of the Index
of Watershed Indicators.
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your Watershed" at:
. Click on the data layer of interest to find
documentation and FTP (File Transfer Protocol) addresses.
Data Sufficiency Thresholds
Data sufficiency thresholds levels were set for the three data sets used to characterize
source water condition (see maps 3a, 3b, and 3c). These threshold levels ensure that
sufficient data exists to make a valid judgement of source water condition.
Notes on Interpreting this Information
• Data Somewhat Consistent/Additional Data Needed
See "Plans to Improve this Data Layer" for details.
• The assignment of community water systems to the specific watershed
is based in some cases on incomplete locational information and may
not accurately represent the water system 's source water.
• The watershed boundaries used in the IWI are bigger and different
than the source water boundaries for many water systems.
• Water systems may use water sources that are in more than one
watershed, a fact that is not captured in the IWI characterization.
• Some public supplies may use ground water sources from a confined
aquifer, which may not be representative of the source water condition
in the watershed.
• This source water condition map combines into one index the three
disparate data sets as listed above. All of the notes listed for the
component data sets must be taken into account when using this map.
Plans to Improve this Data Layer
The partial characterization of source water condition in the Index of Watershed
Indicators Phase 1 will improve in future phases through four ongoing actions in the
drinking water program:
a) States are required, under the amendments of the Source Water Assessment
Provisions of the 1996 Safe Drinking Water Act (SDWA) Amendments, to complete
assessments by 1998 for all public water systems;
b) EPA will work with the States to access more complete source water information;
c) EPA will develop a more robust ground water data layer in future phases of the Index
of Watershed Indicators through collaboration with States, other Federal agencies, and
drinking water utility associations; and
d) EPA will incorporate in the Safe Drinking Water Information System (SDWTS) more
complete geographic references to public water system intakes and wellheads, including
latitude/longitude coordinates.
For More Information Contact:
Database Owner:
U.S. Environmental Protection Agency
Individual Contact
Carl Reeverts; 202 260-7273; E-mail: Reeverts.Carl@epamail.epa.gov
Data Source:
This map is a composite of three maps shown in the Supplemental Maps section.
Sources of data in these maps are:
Map 3a; State FY 1994 305(b) assessments,
Map 3b; SDWTS Violations and Treatment Data,
Map3c; STORET data .
Page 13
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4. Contaminated Sediments
1980 -1993
Analysis of Alaska and
Hawaii reserved for Phase 2.
Watershed Classification
L ~1 Inconclusive Data
I I Mxterate Degree of Concern
I I High Degree of Concern
BB No Data for Assessment
Index of Watershed
Indicators
Sources: U.S. Environrrental Protection Agency
National Sediment Inventory
-------
Map 4
Importance of Contaminated Sediments
Certain chemicals in water tend to bind to particles and collect in bottom
sediments. When present at elevated levels in sediments, chemicals can kill or
harm bottom dwelling organisms. Pollutants in sediments can also accumulate
in aquatic organisms and move up the food chain to fish, shellfish and
eventually humans. Because of these effects, the presence of contaminated
sediment in a watershed is a good indicator of current aquatic condition,
U.S. EPA has recently completed a national assessment of sediment
contamination in waters throughout the United States. As part of this
assessment, U.S. EPA compiled existing sediment chemistry, sediment
toxicity, and fish tissue residue data from individual monitoring stations
throughout the nation. U.S. EPA applied a peer-reviewed weight-of-evidence
evaluation to determine the probability of association with adverse effects to
human health or aquatic life indicated by the data at each monitoring station.
Tier 1 monitoring stations indicate a higher probability of association with
adverse effects, and Tier 2 stations indicate lower to intermediate probability
of adverse effects. Other monitoring stations do not indicate probability of
association with adverse effects.
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your
Watershed" at: Click on the data layer of
interest to find documentation and FTP (File Transfer Protocol) addresses.
Data Sufficiency Thresholds
All data U.S. EPA has collected for the National Sediment Inventory (NSI) from
States and other sources, such as Federal agencies, is used. The IWI
distinguishes between watersheds which have no data and those that have too
little data to draw conclusions from.
Notes on Interpreting this Information
• Data Somewhat Consistent/Additional Data Needed
See "Plans to Improve this Data Layer for details.
• Currently the NSI represents over 20,000 sites but covers only 11% of
the Nation 's river, lake and coastline sediments. Additional data needs
to be collected assessing sediment conditions at more locations.
• Watersheds with 20 or more Tier 1 stations and greater than 75% of all
stations classified as either Tier 1 or Tier 2 have a high degree of
concern; those with 10 or more Tier 1 stations and greater than 75% of
all stations classified as Tier 1 or Tier 2 have a moderate degree of
concern.
Plans to Improve this Data Layer
To improve the data quality of this data layer, U.S. EPA will continue to
coordinate with U.S. EPA regional offices, States, Tribes, and others to compile
and identify additional data. In addition, U.S. EPA is committed to promoting
state-of-the-art assessment methods to determine whether sediment at a site
poses a risk to human or ecological health.
For More Information Contact:
Database Owner
U.S. EPA Office of Science and Technology
Standards and Applied Science Division
Individual Contact
Jim Keating
E-mail: keating.jim@epamail.epa.gov
Phone: (202) 260-3845
Data Source:
National Sediment Inventory (NSI), 1980-1993
U.S. Environmental Protection Agency, Office of Science and
Technology
U.S. EPA was specifically mandated by the Water Resources Development
Act to compile all existing information on the quantity, chemical and physical
composition, and geographic location of pollutants in aquatic sediment,
including identification of those sediments which are contaminated. As part of
this effort, U.S. EPA collects and evaluates sediment and fish tissue data from
State, U.S. EPA regional, and other monitoring programs. The data are stored
in the National Sediment Inventory
Page 15
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5. Ambient Water Quality Data - Four Toxic Pollutants
Copper, Chromium (Hexavalent), Nickel and Zinc
1990-1995
Analysis ill Alaska and
liauaii reserved lor Phase 2
Watershed Classification
| | 0 - 10° o Observations in Exceedence of National Criteria
Q | 11 - 50% Observations in Exceedence of National Criteria
| | >50% Observations in Exceedence of National Criteria
[^H Data Sufficiency Threshold Not Met
Index of Watershed
Indicators
Sources: U.S. Emironmental Protection Agency:
Storage aid Retrieval (STORE!") System
1W7
-------
Map 5
Importance of Ambient Water Quality Data - Four Toxic
Pollutants
This data layer describes the degree to which monitoring of ambient
concentrations of selected toxic pollutants (copper, nickel, zinc and chromium
(hexavalent)) indicate an exceedance of the national chronic level criteria
developed by U.S. EPA for the pollutant. (Note that State water quality
standards may differ from these numbers.)
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your
Watershed" at: . Click on the data layer of
interest to find documentation and FTP (File Transfer Protocol) addresses.
Data Sufficiency Thresholds
Each watershed must contain at least 20 observations representing a minimum
of five sites over the six year period, 1990-1995.
Notes on Interpreting this Information
• Data Somewhat Consistent/Additional Data Needed
See "Plans to Improve this Data Layer" for details.
• Ambient water quality data from STORET showing percent exceedences
over a six year period (J 990-1995) are used The criteria used to
calculate exceedences reflect whether fresh or marine waters were being
sampled Marine waters were considered to be those with hardness >
1000 mg/l Freshwater criteria for copper, nickel and zinc were adjusted
for hardness levels at each monitoring site.
• The current STORET system contains limited information regarding data
quality, and users do not always use identical methods or criteria to assess
their waters. Also, much metals data in STORET was collected without the
use of ultra clean monitoring methods recommended by the USGS
• Most monitoring undertaken by States and Tribes is focused on rivers,
lakes and estuaries with suspected or identified pollution problems.
Assessments based on this type of monitoring may not be
representative of the whole watershed and may overestimate the
degree of concern.
• National criteria are used because they can be applied across all
watersheds universallv, but they are not necessarily the levels in State
water quality standards
Plans to Improve this Data Layer
• U.S. EPA will explore the use of a translation formula to convert total
metals data to the dissolved form.
• U.S. EPA is modernizing the STORET system to make it easier to access
data, store information about data quality and equipment used to acquire
the data, and expand the fields to store biological and habitat data.
• The U.S. Geological Survey is addressing the issue of metals monitoring
by developing ultra clean trace metals monitoring methods. The USGS
offers classes teaching these new methods to water quality monitoring
professionals.
For More Information Contact:
Database Owner:
U.S. Environmental Protection Agency, Office of Water
Individual Contact:
Louis Hoelman
E-mail: Hoelman.Louie@epamail.epa.gov
Phone: 202 260-7050
Data Source:
STOrage and RETrieval System (STORET), 1990-1995
U.S. Environmental Protection Agency, Office of Water.
U.S. EPA maintains a national database, the STOrage and RETrieval
(STORET) system, containing over 250 million observations of water quality
monitoring data from multiple sources both public and private. Most recently,
the U.S. Geological Survey's National Water Quality Assessment (NAWQA)
data has been added to the STORET system.
STORET is designed to store and disseminate basic information on chemical,
physical and biological quality of the nation's waterways within and contiguous
to the United States.
Additional Information
For additional information on STORET or data in STORET, call the
STORET hotline at 1-800-424-9067
Page 17
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6. Ambient Water Quality Data - Four Conventional Pollutants
Ammonia, Dissolved Oxygen, Phosphorus and pH
1990 -1995
Analysis at" Alaska and
Hauaii reserved for Phase 2
Watershed Classification
I | 0 -1 OP/o Observations in Exceedence of Selected Reference Level
L I 11 - 25% Observations in Exceedence of Selected Reference Level
|_ | >25% Observations in Exceedence of Selected Reference Level
§| Data Sufficiency Threshold Not Met
Index of Watershed
Indicators
Sources: U.S. EmironriKiital Protection Agency:
Storage aid Retrieval (STORE!) System
-------
Map 6
Importance of Ambient Water Quality Data - Four
Conventional Pollutants
This data layer describes the degree to which monitoring of ambient
concentrations of selected conventional pollutants (ammonia, phosphorus, pH,
and dissolved oxygen) indicate an exceedance of a national reference level
developed by U.S. EPA for the pollutant. For this data layer, ambient water
quality data from STORET showing percent exceedences over a six year period
(1990-1995) are used. The reference levels for each conventional pollutant are:
ammonia (recommended chronic levels for ammonia were taken from Ambient
Water Quality Criteria for Ammonia, EPA 440/5-85-001, p. 97 and reflect
temperature and pH adjustments), phosphorous (0.1 mg/1), and pH (6.0 to 9.0 ).
Dissolved oxygen is not a pollutant, but is a measure of oxygen demanding
wastes. The reference for dissolved oxygen levels is 5 mg/1 Note that State
water quality standards may differ from these concentrations .
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your
Watershed" at: Click on the data layer of
interest to find documentation and FTP (File Transfer Protocol) addresses.
Data Sufficiency Thresholds
Each watershed must contain at least 20 observations representing a minimum of
five sites over the six year period, 1990-1995.
Notes on Interpreting this Information
» Data Somewhat Consistent/Additional Data Needed
See "Plans to Improve this Data Layer" for details.
• The current STORET system contains limited information regarding
data quality and STORET users do not necessarily use identical
methods or criteria to assess their waters.
» Most monitoring undertaken by States and Tribes is focused on rivers,
lakes and estuaries with suspected or identified pollution problems.
Assessments based on this type of monitoring may not be representative
of the whole watershed and may overestimate the degree of concern.
• National reference levels are used because they can be applied across
all watersheds universally, but they are not necessarily of concern to
individual States.
Plans to Improve this Data Layer
• U.S. EPA is modernizing the STORET system to make it easier to
access data; store information about data quality and equipment used to
acquire the data; and expand the fields to store biological and habitat
data.
For More Information Contact:
Database Owner:
U.S. Environmental Protection Agency, Office of Water
Individual Contact:
Louis Hoelman
E-mail: Hoerman.Louie@epamail.epa.gov
Phone: 202 260-7050
Data Source:
STOrage and RETrieval System (STORET), 1990-1995
U.S. Environmental Protection Agency, Office of Water.
U.S. EPA maintains a national database, the STOrage and RETrieval (STORET)
system, containing over 250 million observations of water quality monitoring
data from multiple sources both public and private. Most recently, the U.S.
Geological Survey's National Water Quality Assessment (NAWQA) data has
been added to the STORET system.
STORET is designed to store and disseminate basic information on chemical,
physical and biological quality of the nation's waterways within and contiguous
to the United States.
Additional Information
For additional information on STORET or data in STORET, call the STORET
hotline at 1-800-424-9067.
Page 19
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7. Wetland Loss Index
Combines Both Recent (1982 -1992)
and Historic (1780s - 1980s) Wetland Loss
AnaK sis ot Alaska and
1 lauai i iv-sen ed for Phase 2
Watershed Classification
I | Low Level of Wetland Loss
I | Moderate Level of Wetland Loss
| | High Level of Wetland Loss
Index of Watershed
Indicators
Sources: Natural Resources Conservation Service
U.S. Fish and Wildlife Sen ice
June 23, 1SW
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Map?
Importance of Wetland Loss Index
Wetlands make important contributions to the health of aquatic systems on a watershed
basis by purifying water, filtering runoff, abating floods, and decreasing erosion. In
addition, wetlands provide habitat for countless numbers of plants and animals including
over 40% of all federally listed threatened or endangered species. Many wetland plants
and animals support recreation and commercial industries. For example, wetlands act as
nurseries for over 80% of coastal fisheries. In addition, millions of Americans are
annually drawn to wetlands for bird watching, hunting, fishing, and enjoying the natural
beauty of wetland ecosystems. Although wetland loss rates are slowing, the United
States continues to lose approximately 70,000 to 90,000 acres of wetlands on non-
federal, rural lands each year.
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your Watershed"
at: Click on the data layer of interest to find
documentation and FTP (File Transfer Protocol) addresses.
Description of the Data Layer
Recent wetlands loss rates (Map 7 a, Natural Resources Inventory (NRI), 1982-1992)
were combined with historic loss rates (Map 7b, National Wetlands Inventory (NWI),
1780s-1980s) to form an index. The combined index is a more robust indicator of
watershed condition than either loss rate used independently.
• Natural Resources Inventory. Natural Resources Conservation Service (NRCS)
reports on wetland acreage on rural, non-federal lands that constitute about 75% of
the Nation's land base. (Reported at 6-digit accounting unit)
• National Wetlands Inventory. The U.S. Fish and Wildlife Service maintains wetlands
acreage data on federal and non-federal lands. (State level)
To create the Wetlands Loss Index, The IWI assigned the appropriate NWI State data to
Accounting Units and combined it with NRI data. The following chart was used to
assign scores (0 = low level of wetland loss, 1 = moderate level of wetland loss, and 2 =
high level of wetland loss)
NRI: % loss between 1982 and 1992
(by 6 digit accounting unit)
NWI Historic % loss from
1780s to 1980s
(by State)
Data Sufficiency Threshold
All available data were used
<30%
30-70%
>70%
0
1
2
1
1
}
2
2
2
Notes on Interpreting this Information
• Data Need to be Much More Consistent/Much Additional Data Needed
See "Plans to Improve this Data Layer" for details.
• Existing inventories of acreage change are national in scope and designed to provide
information on national -wetlands losses and gains by wetland type They were not
designed to track wetland change on a -watershed basis and, in most cases, do not
provide robust State or -watershed information
• NWI and NRI were designed to answer different questions and have different
sampling procedures. NRI data used in this analysis were adjusted to reflect
differences and to account for some changes in NRCS's data collection methods.
Unlike the other 14 IWI data layers, this data is reported at the 6 digit accounting
unit scale (each 6 digit unit contains several 8 digit units), which IWI interpolated to
the 8 digit area
Plans to Improve this Data Layer
1 U.S. EPA is working towards reporting on both the quantity and quality of wetlands.
However, wetland biological monitoring programs are still in their infancy. As States
establish wetland monitoring programs and include this information in their 305(b)
reports, better data will be available for this data layer
2. U.S EPA is continuing to work with the USFWS and NRCS to monitor wetland loss
and report improvements in wetland acreage. The Federal Geographic Data Committee
Wetlands Subcommittee is exploring new approaches of tracking wetland acreage,
reporting more frequently, and reporting at the 8-digit watershed level
For More Information Contact:
Database Owners:
1. NRI: USDA National Resources Conservation Service (NRCS)
2. NWI: U.S. Fish and Wildlife Service (USFWS)
Individual Contacts:
NRI: Bob Kellogg NWI:
E-mail: rkellogg@nhq.nrcs.usda.gov E-mail
Phone: (202)690-0341 Phone
Data Source:
1. Natural Resources Inventory (NRI), 1982 and 1992
2. National Wetlands Inventory (NWI), 1780s-1980s
Additional Information
For information about wetlands, contact:
EPA Wetlands Information Hotline (contractor operated)
1-800-832-7828 ot http://www.epa.gov/OWOW/wetlands/\\etlme html
For additional information about the wetlands data layer, contact:
Tom Danielson, U.S Environmental Protection Agency Wetlands Division
E-mail: Danielson Tomfojepamail.epa.gov Phone (202)260-5299
Page 2!
Tom Dahl
rom_Dahlfa!mail fws.gov
(813)570-5429
-------
8. AquaticAVetland Species at Risk
19%
VVJ
Aiiahsis d' .Alaska and
Hawaii resened for Phase 2
Watershed Record
| | 1 Species Kno\\n to be at Risk
j j 2 - 5 Species Knossn to be at Risk
|~ ! >5 Species Kno\\n to be at Risk
No Recorded Data
Index of Watershed
Indicators
Sources: State Natural Hnitage Dbta Center
Tit Nature Consiavancy
-------
Map 8
Importance of Aquatic/Wetland Species at Risk
This data layer provides information about the presence of species at risk in a given
watershed. The State agency-based Natural Heritage Network and The Nature
Conservancy (TNC) assess the conservation status of plants and animals, and map
out the population occurrences of those species at greatest risk of extinction. This
indicator represents the number of aquatic or wetland-dependent species documented
in a watershed that are classified by the Heritage Network as critically imperiled
(identified by TNC as Gl), imperiled (G2), or vulnerable (G3), or that are listed
under the federal Endangered Species Act (ESA) as threatened or endangered.
The presence of rare or endangered species in a watershed is not necessarily an
indication of poor watershed conditions. Indeed, it more likely indicates the
opposite: in many instances these species persist only in areas of exceptionally high
quality habilal. The presence of species at risk in a watershed indicates, however,
that these watersheds are especially vulnerable to future water quality or habitat
degradation, which could jeopardize the maintenance or recovery of these organisms.
Watersheds considered vulnerable because of the presence of species at risk may
require special attention to protect or restore water quality in order to maintain these
biological values.
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your
Watershed" at: Click on the data layer of
interest lo find documentation and FTP (File Transfer Protocol) addresses.
Access to detailed data on the species at risk documented within a given watershed
should be requested through the relevant State Natural Heritage Data Center. Contact
information for the 48 State programs that provided data to the Index of Watershed
Indicators can be accessed at http://www.heritage.tnc.org/nhp/directory/dirlist.html.
Data Sufficiency Thresholds
1 he presence ol an individual species in a watershed is based on the existence in the
heritage databases ol at least one documented occurrence in that watershed since
l')7() Furtheimore, occurrences must be gco-refercnccd at a precision-level of at
least onc-mmule latitude/longitude. This map includes only species thai meet the
lullowmg two criteria for status and habitat use: 1) Heritage/Conservancy
conservation status of critically imperiled to vulnerable (G1-G3), or federal ESA
status ol threatened or endangered; and 2) dependent on aquatic or wetland habitats
based on selection criteria developed as part of the U.S. EPA Environmental
liulicntiii-s <>/ tt'tifcr (Jutililv in the United,SVd/i'.v report.
Notes on Interpreting this Information
• Data Need to be Much More Consistent/Much Additional Data Needed
See "Plans to Improve this Data Layer "for details.
» State Natural Heritage Data Centers process data according to
consistent inventory and data management standards, producing
information that is comparable from State to State.
* Aquatic inventory efforts and data processing backlogs, however, varv
from State to State. Thus while available data is comparable, level of
data completeness is inconsistent.
• Heritage species occurrence data are not based on comprehensive
inventories of each watershed and major inventory gaps remain,
especially for aquatic species. For this reason, some watersheds may
acluallv have more species at risk than indicated.
• Similarly, lack of data for a watershed cannot be construed to mean
that no species at risk are present. It is not currently possible using this
data set to distinguish between luck of inventory data for a watershed
and the absence of species at risk in that watershed.
Plans to Improve this Data Layer
Working with U.S. EPA's Office of Information Resources Management, plans
are being developed that could improve heritage data consistency among States,
reduce data processing backlogs, and create a more readily accessible national
element occurrence data set. In the short-term, information could be compiled
and mapped for specific groups of organisms (e.g., fish and mussels) to
complement the occurrence information available and reduce watershed data
gaps on the map.
For More Information Contact:
Database Owners:
State Natural Heritage Data Centers
http://www.heritage.tnc.org/nhp/dircclory/dirlist.html
Data compiled and analyzed by The Nature Conservancy
Individual Contact:
Bruce Stein
E-mail: bstein(<(Hnc.org
Phone: 703-841-2711
The basic locational data underlying this map are developed and stored by the State
agency-based Natural Heritage Data Centers. These State data centers document the
location of rare and endangered species for use in environmental planning and
conservation efforts. Eoeational data from 48 States were aggregated and combined
with conservation status and habitat use information maintained by TNC' to develop
this map.
I'agc 23
-------
9. Pollutant Loads Discharged Above Permitted Limits - Toxic Pollutants
1995
v\J
Anah sis of Alaska and
I la\\aji reserved for Pliase 2
Watershed Record
I I No DMR Data Entry Requirements for all Dischargers,
or No NPDES Dischargers
, , No Aggregate Loads in Excess of Total Penrrit Limits
or No Pennitted Dischargers
I I Up to 20% Average Load Over Pennitted Limits
Z] IVtore Than 20% Average Load Over Pennitted Limits
Insufficient Data for >10%of Major Dischargers or for >50%
of Minor Dischargers when No Major Dischargers Present
Index of Watershed
Indicators
Sources: U.S. Environmental Protection Agency
Permit Compliance System
Ti.t93.7rl2
-------
Map 9
Importance of Pollutant Loads Discharged Above Permitted
Limits - Toxic Pollutants
As one of the activities to maintain water quality in the US, the Clean Water Act requires
that U.S. EPA or States set limits through permits under the National Pollutant Discharge
Elimination System (NPDES) on the amount of pollutants that facilities such as sewage
treatment or industrial plants may discharge into a waterbody. Limits for these
discharges are set according to national technology-based standards and the conditions of
the waters that receive the discharge based on State water quality standards. This data
layer adds up the total amount of pollutants allowed to be discharged through NPDES
permits into each watershed, and compares this total amount to the total amount of
pollutants actually discharged to determine the amount in excess of the allowable
discharge.
Watersheds with pollutant loads greater than the total permit limits of all facilities are
considered vulnerable to future declines in aquatic health. This data layer provides
insight into whether the total of all discharges exceeds the total of all permitted limits for
all toxic pollutants named in the permits. Such toxic pollutants include cadmium,
copper, lead, mercury, and others. Watersheds with the highest scores have greater
potential for possible future environmental decline due to toxic pollutant exceedences.
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your Watershed" at:
. Click on the data layer of interest to find
documentation and FTP (File Transfer Protocol) addresses.
Data Sufficiency Thresholds
A watershed was considered to have insufficient data if more than 10% of the major
facilities in the watershed did not have Discharge Monitoring Form (DMR) data in the
Permit Compliance System (PCS), or, if there were no major facilities, more than 50% of
the minor facilities in the watershed did not have DMR data in PCS.
Notes on Interpreting this Information
* Data Consistent/Sufficient Data Collected (permittees must follow NPDES
requirements in reporting data)
See "Plans to Improve this Data Layer for details.
* The discharge data from "Minor" facilities (municipal facilities with flow less
than 1 million gallons a dav, or non-municipal facilities with a major rating
code (a code assigned based on such factors as type of waste, toxicity, flow,
and distance from a drinking water source) below the minimum requirement
to be classified "Major") are not required to be entered into PCS. Therefore,
this data laver mav not represent all permitted dischargers in a watershed.
• Due to inconsistent reporting of monitoring data below the method detection
limit across the country, DMR data below detection were not used in this
analysis. Facilities that had a mixture of data above and below the detection
limit were included in the analysis but only data above detection were used to
calculate loadings.
* Violations ofdailv maximums, where there are no monthly average limits, were
evaluated as 30 days of violation except chlorine, which was calculated as only
a one-day violation. This minimizes the impact of chlorine while maximizing
the impact of the other toxic pollutants. Due to the frequency at which
chlorine is monitored and the probability of a short duration violation,
chlorine violations, if treated as 30 days of violation, would significantly mask
other toxic pollutant violations which may have more impact on the receiving
waterbodv (chlorine dissipates quickly while these other toxic pollutants do
not).
Plans to Improve this Data Layer
The data contained in PCS are of high quality, but the Office of Water and the Office of
Enforcement and Compliance Assurance are still taking actions to improve the data in
order to address: (1) changes in permitting requirements from year to year; (2)
inconsistent reporting from facilities required to submit discharge data; (3) facilities not
required to report discharge data but still responsible for releasing contaminants to
receiving waters; and (4) different PCS parameter codes for the same pollutant, hi
addition, the U.S. EPA plans to provide guidance to regional and State permit writers on
how to enter data more accurately and consistently into PCS.
For More Information Contact:
Database Owner: U.S. EPA, Office of Enforcement and Compliance Assurance
Individual Contact: Steve Rubin E-mail: Rubin.Steven@epamail.epa.gov Phone: (202)
564-7052
Data Source: Permit Compliance System (PCS), U.S. EPA From the 1995 self-
monitoring measurement data reported on the NPDES DMR form
Additional Information
US EPA Regional Contacts
1 - Robin Neas 2 - Roger K Vann
E-mail. Neas Robin@epamail epa gov E-mail Vann Roger@epamail epa gov
Phone: 617/565-4869 Phone 212/637-3321
3 - Edna Jones 4 - Mike Donehoo
E-mail' Jones.Edna@epamail.epa.gov E-mail. Donehoo.Mike@epamail epa gov
Phone: 215/566-5795 Phone 404/562-9745
5 - Arnie Leder 6 - Cathy Bius
E-mail. Leder.Amold@epamailepa.gov E-mail Bius.Cathenne@epamail epa gov
Phone 312/886-0133 Phone 214/665-6456
7 - Michael Rosenbaum 8 - Josie Hernandez
E-mail' Rosenbaum Mike@epamail.epa gov E-mail' Hernandez Josie@epamail epa.gov
Phone: 913/551-7450 Phone. 303/312-7079
9-CareyHouk 10 - Jeannine (JJ) Brown
E-mail Houk Carey@epamail epa gov E-mail: BrownJeannine@epamail epa gov
Phone: 415/744-1886 Phone. 206/553-1058
Page 25
-------
10. Pollutant Loads Discharged Above Permitted Limits - Conventional Pollutants
1995
\4J
Analysis of Alaska and
tfcmaii reserved for Phase 2
Watershed Record
I '.. 1 No DMR Data Entry Requirements for all Dischargers.
or No NPDES Dischargers
~ZH No Aggregate Loads in Excess of Total Peirrrit Limits
or No Pennitted Dischargers
I I Up to 40% Average Load Over Pennitted Limits
H More Than 40% Average Load Over Pennitted Limits
Hi! Insufficient Data for >10%of Major Dischargers or for >50%
of Minor Dischargers when No Major Dischargers Present
Index of Watershed
Indicators
.Sources: U.S. Emironmental Rxiteetion Agency
Permit Compliance System
June 25. i
-------
Map 10
Importance of Pollutant Loads Discharged Above Permitted
Limits - Conventional Pollutants
As one of the activities to maintain water quality in the U.S., the Clean Water Act
requires that U.S. EPA or States set limits through permits under the National Pollutant
Discharge Elimination System (NPDES) on the amount of pollutants that facilities such
as sewage treatment or industrial plants may discharge into a waterbody. Limits for these
discharges are set according to national technology-based standards and the conditions of
the waters that receive the discharge based on State water quality standards. This data
layer adds up the total amount of pollutants allowed to be discharged through NPDES
permits into each watershed, and compares this total amount to the total amount of
pollutants actually discharged to determine the amount in excess of the allowable
discharge.
Watersheds with pollutant loads greater than the total permit limits of all facilities are
considered vulnerable to future declines in aquatic health. This watershed vulnerability
data layer provides insight into whether the total of all discharges by facilities exceeds the
total of all permitted limits for all conventional pollutants named in the permits. Such
conventional pollutants include biochemical oxygen demand, total suspended solids,
nutrients, and others. Watersheds with the highest scores have greater potential for
possible future environmental decline due to conventional pollutant exceedences.
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your Watershed" at:
. Click on the data layer of interest to find
documentation and FTP (File Transfer Protocol) addresses.
Data Sufficiency Thresholds
A watershed was considered to have insufficient data for this analysis if greater than 10%
of the major facilities in mat watershed did not have Discharge Monitoring Report
(DMR) data in the Permit Compliance System (PCS), or, if there were no major facilities,
more than 50% of the minor facilities in that watershed did not have DMR data in PCS.
Notes on Interpreting this Information
* Data Consistent,'Sufficient Data Collected (permittees must follow NPDES
requirements in reporting data)
See "Plans to Improve this Data Layer "for details.
* The discharge data from "Minor' facilities (municipal facilities with flow less
than 1 million gallons a day, or non-municipal facilities with a major rating
code (a code assigned based on such factors as type of waste, toxicity,flow,
and distance from a drinking water source) below the minimum requirement to
be classified "Major") are not required to be entered into PCS Therefore,
this data layer may not represent all permitted dischargers in a watershed.
* Due to inconsistent reporting of monitoring data below the method detection
limit across the country, DMR data below detection were not used in this
analysis. Facilities that had a mixture of data above and below the detection
limit were included in the analysis but only data above detection were used to
calculate loadings.
• Violations of daily maximums, where there are no monthly average limits, were
evaluated as 30 days of violation.
Plans to Improve this Data Layer
The data contained in PCS are of high quality, but the Office of Water and the Office of
Enforcement and Compliance Assurance are still taking actions to improve the data in
order to address: (1) changes in permitting requirements from year to year; (2)
inconsistent reporting from facilities required to submit discharge data; (3) facilities not
required to report discharge data but still responsible for releasing contaminants to
receiving waters; and (4) different PCS parameter codes for the same pollutant, hi
addition, the U.S. EPA plans to provide guidance to regional and State permit writers on
how to enter data more accurately and consistently into PCS.
For More Information Contact:
Database Owner: U.S. EPA, Office of Enforcement and Compliance Assurance
Individual Contact: Steve Rubin, E-mail: Rubin.Steven@epamail.epa.gov Phone: (202)
564-7052
Data Source
Permit Compliance System, U.S. Environmental Protection Agency
From the 1995 self-monitoring measurement data reported by NPDES Discharge
Monitoring Report (DMR) form.
Additional Information
U.S. EPA Regional Contacts-
1 - Robin Neas
E-mail: Neas.Robm@epamail.epa.gov
Phone: 617/565-4869
3 - Edna Jones
E-mail: Jones.Edna@epamail epa.gov
Phone. 215/566-5795
5 - Arrue Leder
E-mail Leder Arnold@epamail.epa.gov
Phone: 312/886-0133
7 - Michael Rosenbaum
E-mail: Rosenbaum.Mike@epamail.epa gov
Phone: 913/551-7450
9 - Carey Houk
E-mail Houk.Carey@epamail.epa gov
Phone: 415/744-1886
2 - Roger K. Vann
E-mail: Vann.Roger@epamail epa.gov
Phone: 212/637-3321
4 - Mike Donehoo
E-rnaif Donehoo.Mike@epamail epa.gov
Phone' 404/562-9745
6 - Cathy Bius
E-mail: Bius.Catherine@epamail epa.gov
Phone. 214/665-6456
8 - Josie Hernandez
E-mail: Hernandez.Josie@epamail.epa.gov
Phone: 303/312-7079
10 - Jeannine (JJ) Brown
E-mail Brown.Jeanmne@epamail.epa.gov
Phone. 206/553-1058
Page 27
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11. Urban Runoff Potential
1990
Analysis of Alaska and
Ha\\ai i reserved for Phase 2
Watershed Estimates
^] < 1% Land Area Above 25% Imperviousness
- 4% Land Area Above 25% Imperviousness
I >4% Land Area Above 25% Imperviousness
Insufficient Data to Make Estimates
Index of Watershed
Indicators
Sources: U.S. Census Bureau
U.S. Geological Survey
June ?Q 1997
-------
Map 11
Importance of Urban Runoff Potential
Imperviousness is a useful indicator to predict impacts of land development
on aquatic ecosystems. Studies have linked the amount of imperviousness to
changes in the hydrology, habitat structure, water quality and biodiversity
of aquatic ecosystems (Watershed Protection Techniques, Vol. 1, No. 3, Fall
1994). Increased imperviousness can change the hydrology of a receiving
stream, increasing runoff volume and rate and decreasing the receiving
streams capacity to handle floods.
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your
Watershed" at: . Click on the data layer of
interest to find documentation and FTP (File Transfer Protocol) addresses.
Description of the Data Layer
This indicator was developed based on the block group, a geographic area
defined by the U.S. Census Bureau for purposes of reporting demographic
data. A database of urban area was developed based on the 1978 U.S.
Geological Survey (USGS) land use data and estimated population growth
from 1978 to 1990. A relationship between population growth and
expansion of urban area was established for each block group to estimate the
1990 urban area and imperviousness area for each block group. An urban
runoff potential was then calculated for each block group using a simple
runoff estimation method based on regional rainfall characteristics and the
amount of urban and imperviousness area. This urban runoff potential was
then aggregated at the 8-digit watershed level to determine an urban runoff
potential indicator for the Index of Watershed Indicators.
Data Sufficiency Thresholds
All block group data were used.
Notes on Interpreting this Information
• Data Somewhat Consistent/Additional Data Needed
See "Plans to Improve this Data Layer "for details.
• Indicator represents 1990 urban conditions. Changes since 1990
are not reflected.
• The relationship developed to estimate 1990 urban area and
imperviousness area may not accurately reflect current conditions.
• Stormwater management practices are not included in the
determination of the indicator. These practices, if properly
designed and maintained, can mitigate impacts caused by
imperviousness.
Plans to Improve this Data Layer
Plans to be determined.
For More Information Contact:
Database Owner:
U.S. Environmental Protection Agency, Office of Water
Individual Contact:
John Kosco
E-mail: Kosco.John@epamail.epa.gov
Phone: 202 260-6385
Data Source:
U.S. Census Bureau - 1990 population and housing, 1980 population
U.S. Geological Survey - GIRAS Land Use, 1978
Page 29
-------
12. Index of Agricultural Runoff Potential
(Based Upon Nitrogen, Sediment and Pesticide)
1990 -1995
AnaKsis at' Alaska and
Hawaii reserved for Phase 2
Watershed Classification
| | Low Level of Potential Impact
| | Moderate Level of Potential Impact
| | High Level of Potential Impact
BHii Insufficient IWI Data
Index of Watershed
Indicators
Source: Natural Resources Conservation Service
-------
Map 12
Importance of Index of Agricultural Runoff Potential
A composite index was constructed to show which watersheds had the
greatest potential for possible water quality problems from combinations of
pesticides, nitrogen, and sediment. Watersheds with the highest composite
score have a greater risk of water quality impairment from agricultural
sources than watersheds with low scores. Watersheds could be ranked high
because of a very high ranking of a single component, or moderately high
rankings from two or more components.
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your
Watershed" at: Click on the data
layer of interest to find documentation and FTP (File Transfer Protocol)
addresses.
Description of the Data Layer
The composite indicator was constructed by ranking watersheds for each of
the three components -- potential pesticide runoff, potential nitrogen runoff,
and potential in-stream sediment loads — and then summing the rankings
for each watershed. This procedure weighted each of the three components
equally. Individual maps for the three components are shown in
'''Supplemental Maps" following
Data Sufficiency Thresholds
No data sufficiency threshold was applied.
Notes on Interpreting this Information
• Data Consistent/Sufficient Data Collected
See "Plans to Improve this Data Layer"for details,
• The composite indicator primarily represents sources of pollutants
from cropland. It does not include any components for rangeland,
pastureland, or privately managed forest land.
• This composite map combines three disparate agricultural
vulnerability indicators - pesticide runoff, nitrogen runoff, and in-
stream sediment loads. See the individual data layer maps in
"Supplemental Maps "for additional information and caveats for
each of these component indicators.
Plans to Improve this Data Layer
Efforts will be made to include additional vulnerability components for
rangeland, pastureland, and forest land.
For More Information Contact:
Database Owner
U.S. Department of Agriculture, NRCS
Individual Contact
Robert Kellogg, NRCS/USDA
E-mail: robert.kellogg@usda.gov
Phone:(202)690-0341
Data Source:
National Resources Inventory
U.S. Department of Agriculture, Natural Resources Conservation
Service
Page 31
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13. Population Change
1980-1990
Aiiah sis of Alaska and
Hawaii reserved for Phase 2
Watershed Census
Declined or No Change
10 - 7% Increase
| >7% Increase
Insufficient IWI Data
Index of Watershed
Indicators
Source: U.S. Census Bureau
JunelZ 1597
-------
Map 13
Importance of Population Change
The growth of human populations can result in increased pollution of our
waters as land cover and land uses change. These changes include
construction impacts, increased impervious surfaces, loss of wetlands, and
increased sewage flows. Population often increases in areas with growing
sources of employment, also bringing industrial and commercial impacts as
well. This data layer identifies changes in population in watersheds based
on the U.S. Census Bureau data. It assigns scores based on whether the
population has remained stable or decreased, increased from 0 to 7%, or
increased more than 7%.
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your
Watershed" at: . Click on the data layer of
interest to find documentation and FTP (File Transfer Protocol) addresses
Data Sufficiency Thresholds
Watersheds with a density of less than 6.88 people per square mile were
placed in the category of "declined or no significant change." Density
values less than 6.88 represent the 5th quantile and are considered to be so
low as to have minimal impact on water quality. Population changes
between zero and 7 percent (but with densities greater than 6.88) were
placed in the second category, while population changes greater than seven
percent were placed in the third category.
Notes on Interpreting this Information
• Data Consistent/Sufficient Data Collected
See "Plans to Improve this Data Layer 'for details.
• The calculation of population change was done at the 8-digit
Cataloguing Unit level which could mask areas of change in
watersheds that have block groups with increasing populations
and block groups with decreasing populations
Plans to Improve this Data Layer
Data will be revised after the next census.
For More Information Contact:
Database Owner
U.S. Census Bureau
Individual Contact
TodDabolt,U.S. EPA
202 260-3697
E-mail: Dabolt.Thomas@epamail.epa.gov
Data Source:
U.S. Census Bureau, 1980-1990.
Page 33
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14. Hydrologic Modification Caused by Dams
1995-1996
Analysis of Alaska and
1 Ia\\aii reserved for Phase 2
Watershed Classification
| | Low Volumes of Impounded Water
| | Moderate Volumes of Impounded Water
~ | High Volumes of Impounded Water
No Recorded Dams
Index of Watershed
Indicators
Source: U.S. Amn Corps of Puiginoers
-------
Map 14
Notes on Interpreting this Information
Importance of Hydrologic Modification Caused by Dams
The health of the aquatic system in a watershed can be compromised by
extensive impoundment or hydrologic modification of water resources.
This index shows the relative dam storage capacities in watersheds, which
provides a picture of the relative degree of modification of hydrologic
conditions in a watershed. This data is used by Federal Emergency
Management Agency to assess overall safety hazards posed by dams in the
United States. The data can also be used to analyze needs and target
resources for navigation, flood control, water supply, hydroelectric power,
environmental restoration, wildlife protection, and recreational projects.
This database is an inventory of U.S. dams in excess of six feet in height
and a maximum water impounding capacity of at least fifty acre feet; or
dams at least twenty-five feet in height and a maximum water
impoundment capacity in excess of fifteen acre-feet. It contains
information on 75,187 dams throughout the U.S. and its territories. The
U.S. Army Corps of Engineers updates the database with assistance from
the States and territories
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your
Watershed" at: Click on the data
layer of interest to find documentation and FTP (File Transfer Protocol)
addresses.
Data Sufficiency Thresholds
All data is used for this data layer except that on a river with multiple dams,
waters are not counted twice.
• Data Somewhat Consistent/Additional Data Needed
See "Plans to Improve this Data Layer" for details.
• The database does not reflect actual stream channel modifications.
• The database does not reflect the different uses of impounded
"waters.
Plans to Improve this Data Layer
EPA intends to deal better with the impacts of small dams, dry dams, and
reservoirs. In addition, the Nature Conservancy is developing an Index of
Hydrologic Modification that in time may provide more predictions of
aquatic resource modification.
For More Information Contact:
Database Owner:
U.S. Army Corps of Engineers
Individual Contact:
Bob Bank
E-mail: Robert,Bank@inet.hq.usace.army.mil
Phone:(202)761-1660
Data Source:
National Inventory of Dams Database
U.S. Army Corps of Engineers. 1995-199
Page 35
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15. Estuarine Pollution Susceptibility Index
Based Upon Pollution Loads and Pollution Retention Characteristics of Estuaries
1989-1991
Analysis at'Alaska and
Hawaii reserved for Phase 2
Coastal Watershed Classification
| | Low Susceptibility
| | Moderate Susceptibility
I | High Susceptibility
Index of Watershed
Indicators
Source: National Oceanic and Atmospheric Administration
6ERA
June 22,1997
Tl -1-9?^ 3rt
-------
Map 15
The Importance of Estuarine Pollution Susceptibility Index
Coastal lands comprise approximately 11 percent of the area of the United States;
however, this area contains nearly 45 percent of the population. Indications are that
coastal population growth will continue to increase. As these areas come under
increased stress, better information will be required in order to initiate effective
management strategies. The Estuarine Pollution Susceptibility Index provides a
tracking method for the susceptibility to pollution of coastal watersheds.
Susceptibility is defined as the relative vulnerability of an estuary to concentrations
of dissolved and particulate substances.
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your Watershed" at:
. Click on the data layer of interest to find
documentation and FTP (File Transfer Protocol) addresses.
Description of the Data Layer
National Oceanic and Atmospheric Administration (NOAA) built the National Estuarine
Inventory (NEI) around a watershed-based spatial framework which defined and
characterized the nation's estuarine resource base in an effort to develop a national
estuarine assessment capability. The NEI framework was included in a larger Coastal
Assessment Framework (CAF) which identifies all watersheds associated with the coast.
The CAF framework data includes a set of approximately 700 cataloging units which are
used with geographic information systems to conduct a variety of spatial analyses.
NOAA then applied to these 700 cataloging units a Strategic Assessment for Near
Coastal Waters which quantifies susceptibility to pollution by the dissolved concentration
potential (DCP), the particle retention efficiency (PRE), and by the estimated loadings
and predicted concentrations of nitrogen (N) and phosphorus (P).
The DCP characterizes the effect of dilution and flushing on a per-unit-load of a
dissolved and conservative pollutant to an estuary. The parameter is based on the
fractional freshwater method for predicting the concentration of a pollutant. The DCP
used in conjunction with estimated nutrient loads provides a first order approximation of
nutrient conditions within an estuary. The PRE is based upon an empirical relationship
between sediment trapping efficiency and a capacity to inflow ratio. The PRE assumes
that die relative ability of an estuary to trap sediment correlates to its ability to retain any
associated toxic pollutant.
Currently, NOAA assessments exist for over 130 estuaries within the CAF. The date
for most assessments is 1990, however, the mid-Atlantic and south Atlantic were
updated in 1996. To develop the Index of Watershed Indicators (IWI) data layer,
information from the CAFs was applied to the 150 U.S. Geological Survey (USGS)
cataloguing units of the coastal United States and appropriate scores were assigned.
Data Sufficiency Threshold
All NOAA assessments were used.
Notes on Interpreting this Information
* Data Consistent/Sufficient Data Collected
See "Plans to Improve this Data Layer "for details.
* There are some boundary discrepancies between a few USGS units used in
the IWI assessment and the Coastal Assessment Framework.
Plans to Improve this Data Layer
* Replacing the 22.25 km oceanic boundary with a 12 nautical mile
Territorial Sea and Contiguous Zone boundary;
» Revising some of the boundaries that define the CAF drainage areas to
match the USGS Cataloging units;
* Replacing international boundaries;
» Adding Canadian drainage boundaries;
* Correcting errors based upon user comments.
For More Information Contact:
Database Owner
National Oceanic and Atmospheric Administration
Individual Contact:
NOAA: C. John Klein
E-mail: Iklein@seamail.nos.noaa.gov
Phone: 301-713-3000 ext. 160
Data Source:
U.S. EPA: Greg Colianni
E-mail: Cohanni.Gregory@epamail.epa.gov
Phone: 202-260-4025
1. Coastal Assessment Framework. Digital boundary files. National Oceanic and
Atmospheric Administration (NOAA), 1990.
National Coastal Pollution Discharge Inventory. NOAA/NOS. Unpublished data.
Strategic Assessment for Near Coastal Waters, NOAA. (Separate Reports)
A. Susceptibility and Status of North Atlantic Estuaries to Nutrient Discharges.
NOAA/U.S. Environmental Protection Agency (U.S. EPA). 1989.
B. Susceptibility and Status of South Atlantic Estuaries to Nutrient Discharges.
NOAA/U.S. EPA. 1989.
D. Susceptibility and Status of Gulf of Mexico Estuaries to Nutrient Discharges.
NOAA/U.S. EPA. 1989.
E. Susceptibility and Status of West Coast Estuaries to Nutrient Discharges.
NOAA/U.S. EPA. 1989.
4. National Estuarine Inventory: Physical and Hydrologic Characteristics. NOAA
Unpublished Data
I'aee Y
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Index of Watershed Indicators Phase 2 - Plans for the Future
The information contained in this publication presents the first nationwide index representing the condition and vulnerability of water quality in the
watersheds of the continental United States. In Phase 2 of the Index of Watershed Indicators, we will be improving the information for the 15 indicators,
and adding additional indicators we were not able to include during Phase 1. Phase 2 begins in Summer 1997 and will work to include information on:
Geographic Areas
• Add Alaska and Hawaii
• Add specific information for Native American lands
• Add information about Federally-owned lands
• Work with USGS to correct Cataloguing Unit problems uncovered during the IWI process such as duplicative watershed names and boundary issues,
work with NOAA to correct remaining inconsistencies between NOAA's Coastal Assessment Framework and USGS's Cataloguing Units.
Add Additional Indicators
• Biological integrity
• Habitat
• Groundwater
« Coastal condition (eutrophication and shellfish contamination)
* Air deposition
Natural Processes
• Take account of downstream effects, to capture where a watershed is simply exporting its pollution downstream to another watershed
Surf Your Watershed
• Continue to add additional information to the Internet program "Surf Your Watershed," Users are encouraged to add data to "Surf so it can serve as
the electronic index to all available water quality information (the Internet address is: http://www.epa.gov/surf),
Partners
• Work with data owners and other partners to correct problems identified during the review period that were not addressed during Phase I (e.g. missing
reservoirs in Hydrologic Modification indicator), and add data to both IWI and "Surf Your Watershed"
Monitoring and Information Management
• Work with partners to strengthen monitoring and information management systems that supply data for the Index The National Water Quality
Monitoring Council (formerly the Intergovernmental Task Force on Monitoring Water Quality) will be a key partner in this effort.
Page 38
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Supplemental Maps
Three of the Index of Watershed Indicators data layers -- Map 3: Indicators of Source Water Condition for Drinking Water Systems, Map 7:
Wetland Loss Index 1780 - 1980; 1982 - 1992, and Map 12: Index of Agricultural Runoff Potential -- are aggregates of other maps, each
included here as supplemental maps.
Other IWI data layers are also aggregates of information. Readers are urged to review the Internet site "Surf Your Watershed"
(http://www.epa.gov/surf) to see the data that was used in making each of the maps in the Index of Watershed Indicators,
Page 39
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3a. Rivers and Lakes Supporting
Drinking Water I'ses
1994/1996
Analysis of Alaska and
Ha\\aii it-served tor Phase 2
Percent of Watershed River and Lakes .Assessed
under Clean Water Act Section 305(b) Meeting
Drinking Water Designated Uses
^ SO - 100° o Meet Drinking Water Use
| | 50 - 79° o Meet Drinking Wate Use
^ <50° o Meet Drinking Water Use
[T7v] Insufficient .Assessment Coverage.
or No State Drinking Water Use Designated
Index of Watershed
Indicators
Source: U.S. Environmental Protection Agency
June 2Q I
-------
Map 3 a
Importance of Rivers and Lakes Supporting State Drinking
Water Uses
The drinking water use assessments provided by the States under the Clean
Water Act's Section 305(b) are one of the three data sets used to
characterize source water condition. Water Quality Standards adopted by
the states include both designated uses and criteria to protect those uses.
Drinking water is one of the uses that can be protected. States and Tribes
describe water quality in terms of a waterbody either fully supporting,
threatened, partially supporting, or not supporting the drinking water
designated use.
The percent of assessed waterbodies in a watershed meeting their drinking
water designated use is a partial proxy for the condition of the source waters
used by drinking water systems. It is an indicator of how well drinking
water uses are protected by surface and ground water quality standards
promulgated through the Clean Water Act. Section 305(b) designated use
assessments cannot, however, represent the full source water assessments
authorized by the Safe Drinking Water Act Amendments of 1996,
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your
Watershed" at: . Click on the data layer of
interest to find documentation and FTP (File Transfer Protocol) addresses.
Data Sufficiency Thresholds
Any data reported by States in their 305(b) reports were used in assessing
drinking water use support.
Notes on Interpreting this Information:
• Data Somewhat Consistent/Additional Data Needed
See "Plans to Improve this Data Layer for details.
• The data set containing State assessments for drinking water use is
incomplete either because some States did not designate or assess
their waters for drinking water use, or they assumed that other
uses that were assessed sewed as surrogates for drinking water
use attainment.
• Drinking water assessments are inconsistent across states.
States and Tribes do not have identical water quality standards
or identical methods or criteria to assess their waters.
• Most States and Tribes do not assess all of their waters during the
two-year reporting period, and they may even modify techniques
used or assess different waters every two years.
Plans to Improve this Data Layer
EPA has several initiatives underway to improve the quality of the 305(b)
data to assess drinking water use:
• EPA is working with States, Tribes, other federal agencies, and
other partners to develop a more consistent approach to assessing
both ground waters and surface waters for drinking water use.
• EPA is also working with its partners to achieve comprehensive
coverage of the waters in the nation in the 305(b) report, and
include annual electronic updates of key data elements
• This indicator will be updated using the 1996 and subsequent
database updates as they become available
For More Information Contact:
Database Owner:
US EPA, Office of Wetlands, Ocean and Watersheds
Individual Contact:
Carl Reeverts; E-mail: Reeverts.Carl@epamail.epa.gov
Phone: (202) 260-7273
Data Source:
1. National Water Quality Inventory: 1994 Report to Congress
U.S. Environmental Protection Agency, Office of Water
Washington, D.C. December 1995. EPA 841-R-95-005
2. Waterbody System, 305(b) Cataloguing Unit Dataset, Version 1.0
U.S. EPA, Office of Water. 1994, 1996
Additional Information
For additional information on specific state 305(b) reports contact U.S.
EPA's Barry Burgan at (202) 260-7060.
Page 41
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3b. Surrogates of
Source Water Condition
1991 -1996
Analysis of Alaska and
i la\\aii reserved tor Phase 2
Percent of Population Served by Community Water Systems
in Watersheds with Violations or Treatment in Place for
Chemical Contaminants
| | 0 - 10°/o of Population Served by Community Water Systems
^] 11 - 50% of Population Served by Community Water Systems
~j >50% of Population Served by Community Water Systems
EggE) Data Sufficiency Threshold Not Met
Index of Watershed
Indicators
Souns: U.S. Environmental Protection Agency
Safe Drinking Water Mormation"Sysiern
June 21, I -
-------
Map3b
Importance of Surrogates of Source Water Condition
Safe Drinking Water Information System (SDWIS) surrogate indicators provide one of
the three data sets used to characterize source water condition Map 3. Water systems are
major users of the water resources and have a continual interest in the quantity and
quality of their water supplies. Source water characterizations prompt water systems to
take corrective actions to prevent or respond to violations (including adding additional
treatment) to ensure that the water provided at the tap to consumers meets all drinking
water standards. Indicators developed from the existing SDWIS water system inventory
and violation data are used to flag situations where water systems have or will take
actions because of actual or threatened source water problems. Actions taken by water
systems can be a good surrogate for source water characteristics that may not be
identified through other data sources.
Two indicators were developed from SDWIS data:
a) Population served by Community Water Systems that reported one or more violations
of national health-based drinking water standards during FY 1991 - FY 1996 for
chemical (not microbiological) contaminants that are source related (i.e. inorganic
chemicals, volatile organic chemicals, synthetic organics, and radio-nuclides);
b) Population served by Community Water Systems that have treatment in place in 1996
to remove chemical (not microbiological) contaminants that are source water-related.
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your Watershed" at:
•'http://www.epa.gov/surf/IWI/data>. Click on the data layer of interest to find
documentation and FTP (File Transfer Protocol) addresses.
Data Sufficiency Thresholds
The drinking water data will be considered sufficient to characterize the watershed only
where the population served by community water systems is greater than 50 percent of
the population that resides in the watershed. Community water systems reporting no
chemical violations or treatment in place for chemical contaminants were not included in
the source water assessment (see "Notes on Interpreting this Information")
Notes on Interpreting this Information
* Data Somewhat Consistent/Additional Data Needed
See "flans to Improve this Data Layer for details.
» Water svstems with violations of microbiological standards or treatment to
address microbiological contaminants are not included in this data set.
* The use of violations data from SDWIS as a surrogate indicator to
characterize source water condition has limitations
- Absence of a violation is not to be construed as a statement on the
quality of the source waters (i.e., water systems will take whatever actions
neccssuiy to comply with drinking water standards at the tap);
- Isolations may be the result of water purchased outside the watershed or
othenvise unrepresentative of watershed quality (e.g., from a confined
aquifer)
• The use of treatment objective data from SDWIS as a surrogate indicator
to characterize source water condition has limitations:
- SDWIS data on treatment objectives is not currently a required State
reporting item and is therefore very incomplete, subject to different
interpretations by the States, and potentially of lower quality than required
elements;
- Absence of data showing treatment for source water-related
contaminants is not to be construed as a statement on the quality of the
source waters because the data from SDWIS is known to be incomplete.
Plans to Improve this Data Layer
1) SDWIS is undergoing a major modernization effort to improve data entry and
retrieval and to broaden the accessibility of SDWIS data to new and different users.
2) On-going data quality initiatives will continue to improve the quality of data in
SDWIS.
3) The data reported into SDWIS by the states is undergoing a review by an ongoing
Data Sharing Committee to better meet the need of users.
For More Information Contact:
Database Owner:
U.S. Environmental Protection Agency, Office of Ground Water and Drinking Water
Individual Contact
Carl Reeverts
202 260-7273
E-mail: Reeverts.Carl@epamail.epa.gov
Data Source:
Extract from the Safe Drinking Water Information System (SDWIS), 1996.
SDWIS is a repository of information on the public water systems regulated by EPA
and the States under the Safe Drinking Water Act. Information on public water systems
inventory and violations, as well as State and EPA enforcement actions, are reported by
States to SDWIS on a quarterly basis. SDWIS information is used by EPA
Headquarters and Regions to support implementation and enforcement of the drinking
water program. It is also used to characterize progress of the regulatory program and
the effectiveness in terms of public health protection of the regulations. SDWIS is the
major source of information for the Agency environmental indicators initiatives related
to drinking water.
Page 43
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3c. Occurrence of Chemicals in Surface and (Ground Waters
that are Regulated in Drinking Water
1990-1995
/\nal\Ms 11) Alaska ajkJ
Itmrui reserved for Phase 2
Watershed Classification
^ <5° o of Samples that Exceed Half of MCL Levels
I ] 5 - 25° o of Samples that Exceed Half of MCL Levels
^ -25% of Samples that Exceed HaJf of MCL Levels
KISt] Insufficient Data
Index of Watershed
Indicators
Souru.' I; S Environmoital Protection Agencs
-------
Map 3c
Importance of Occurrence of Chemicals in Surface and
Ground Waters That Are Regulated In Drinking Water
Occurrence of contaminants regulated under the Safe Drinking Water Act in (untreated )
ambient waters is one of the three data sets used to characterize source water condition in
watersheds EPA maintains a national database, the STOrage and RETrieval (STORE!)
system, containing over 250 million observations of water quality monitoring data from
multiple sources both public and private, including the U.S. Geological Survey's
National Water Quality Assessment (NAWQA) data which has been added to the
STORE! system.
This data set includes sampling results in STORET from both surface water and ground
water points for all the chemical contaminants regulated under the Safe Drinking Water
Act. (See list of contaminants and their Maximum Contaminant Levels ( MCLs) in the
more detailed Data Profile for this data layer available on Internet at the address below. )
I he source of the data was limited to that provided by STORE! from 1990-1995
Observations above 50% of the MCL were summed for each watershed
The percent of samples that exceed half of the MCL levels indicate the adequacy with
which drinking water may be protected by surface and ground water quality standards
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your Watershed"
at
• hltp //www cpa.gov/surf/IWl/data>. Click on the data layer of interest to find
documentation and FTP (File Transfer Protocol) addresses.
Data Sufficiency Thresholds
Each watershed must contain at least 5 observations representing a minimum of
five sites over the six year period, 1990-1995.
Notes on Interpreting this Information
• Data Somewhat Consistent/Additional Data Needed
Sec "Plans to Improve this Data Layer for details
• Data were watershed-wide and not specifically related to source
waters used by water systems, therefore, this data should not be
used to pinpoint actual source water impairment in the watershed.
• 7/7e current STORET .system contains limited information regarding
data quality and STORET users do not necessarily use identical
methods or criteria to assess their waters.
• Most monitoring undertaken by States and Tribes is focused on rivers
lakes and estuaries with suspected or identified pollution problems
Assessments based on this type of monitoring may not be representative
of the whole watershed and may overestimate the degree of concern.
• STORET data is incomplete and may misrepresent the occurrence of these
contaminants in the watershed Many States have more complete data on
ambient water quality for these contaminants
Plans to Improve this Data Layer
• EPA is modernizing STORET to make it easier to access data; store
information about data quality and equipment used to acquire the data;
and expand the fields to store biological and habitat data.
• EPA will look into using information from the National Drinking
Water Occurrence Database (NOCD) when it becomes available in
August 1999. It will contain information on the occurrence of both
regulated and unregulated contaminants in public waters systems.
For More Information Contact:
Database Owner: U.S. Environmental Protection Agency, Office of Water
Individual Contact:
Louis Hoelman
E-mail' Hoelman.Louie@epamail epa.gov
Phone 202260-7050
Data Source:
STOrage and RETrieval System (STORET), 1990-1995
U.S. Environmental Protection Agency, Office of Water.
STORET is designed to collect and disseminate basic information on chemical,
physical and biological quality of the nation's waters It is a repository of waler
quality data, including information from ambient, intensive survey, and effluent
water quality monitoring of the waterways within and contiguous to the U.S.
Additional Information
For additional information on STORET or data in STORE! , call the S I ORF I
hotline at 1-800-424-9067
45
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7a. Wetland Loss Measured by the
Natural Resources Inventory
1982 -1992
Anahsis of Alaska and Hawaii
resened tor Phase 2
Watershed Qassification
| | Low Level of Wetland Loss
| | Mxlerate Level of Wetland Loss
^) High Level of Wetland Loss
Index of Watershed
Indicators
Sources: Natural Resources Consen ition Service
June 24, 19J7
-------
Map 7a
Importance of Wetland Loss Measured by the NRI
Wetlands make important contributions to the health of aquatic systems on a watershed
basis by purifying water, filtering runoff, abating floods, and decreasing erosion. In
addition, wetlands provide habitat for countless numbers of plants and animals including
over 40% of all federally listed threatened or endangered species. Many wetland plants
and animals support recreation and commercial industries. For example, wetlands act as
nurseries for over 80% of coastal fisheries. In addition, millions of Americans are
annually drawn to wetlands for bird watching, hunting, fishing, and enjoying the natural
beauty of wetland ecosystems. Although wetland loss rates are slowing, the United
States continues to lose approximately 70,000 to 90,000 acres of wetlands on non-
federal, rural lands each year.
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your Watershed"
at:
. Click on the data layer of interest to find
documentation and FTP (File Transfer Protocol) addresses.
Description of the Data Layer
Natural Resources Conservation Service (NRCS) reports on wetland acreage on rural,
non-federal lands that constitute about 75% of the Nation's land base- (Reported at 6-
digit accounting unit)
Using the 1992 NRI, watersheds were identified that had an 80 percent
probability or greater of having a net wetland loss of more than 2 percent
over the 10-yeai period. Since the NRI is a sample, and not a census, estimates of
wetland acreage in 1982 and 1992 and percent wetland loss have errors associated with
them These standard errors can be estimated from the sample data. The errors are
generally larger in watersheds with fewer NRI sample points, and in watersheds that have
diverse land cover. Assuming that the percent wetland loss for the NRI sampling units is
approximately normally distributed, the probability that the true value exceeds a
pre-determmed value can be calculated from the standard errors.
Wetlands included all palustrine (inland) systems, estuarine systems with vegetation,
non-vegetated estuarine systems classified as permanent open water less than 2 acres in
size, riverine and marine systems not also coded as permanent open water, vegetated
lacustrine (lake) systems less than 40 acres, and non-vegetated lacustrine systems not
also coded as permanent open water. Palustrine wetlands made up 93.9 percent and
esluarinc wetlands made up 4.6 percent of all wetlands. Some wetlands went into federal
ownership betueen 1982 and 1992, and a small amount of federally owned wetlands
were sold Since the NRI collects data on wetlands only on nonfederal land, it was
assumed thai the wetland status of these areas was not affected by changes in ownership
Data Sufficiency Threshold
All available data were used.
Notes on Interpreting this Information
• Data Need to be Much More Consistent/Much Additional Data Needed.
See "Plans to Improve this Data Layer" for details.
• NRI data used in this analysis were adjusted to reflect differences and to
account for some changes in NRCS's data collection methods. Unlike the
other 14 IW1 data layers, these data were estimated at the 6 digit Accounting
Unit scale (each 6 digit unit contains several 8 digit units). The IWl distributed
the Accounting Unit estimates evenly to each of the component 8 digit
Cataloging Units.
• The NRI does not collect data on federal lands and data collection on tribal
lands is not consistent.
Plans to Improve this Data Layer
1) U.S. EPA is working towards reporting on both the quantity and quality of wetlands.
However, wetland biological monitoring programs are still in their infancy. As States
establish wetland monitoring programs and include this information in their 305(b)
reports, better data will be available for this data layer.
2) U.S. EPA is continuing to work with the USFWS and NRCS to monitor wetland loss
and report improvements in wetland acreage. The Federal Geographic Data Committee
Wetlands Subcommittee is exploring new approaches of tracking wetland acreage,
reporting more frequently, and reporting at the 8-digit watershed level.
3) U.S. EPA is looking at other sources of data that could be used as an indicator of
wetland condition such as the increases in impervious surfaces, and housing development
trends.
For More Information Contact:
Database Owners:
NRI: USDA National Resources Conservation Service (NRCS)
Individual Contacts:
NRI: Bob Kellogg
E-mail: rkellogg@nhq.nrcs.usda.gov
Phone: (202)690-0341
Data Source:
Natural Resources Inventory (NRI), 1982 and 1992
Additional Information
For additional information about the wetlands data layer, contact:
Tom Danielson, U.S. Environmental Protection Agency, Wetlands Division
E-mail: Danielson.Tom@epamail.epa.gov Phone: (202) 260-5299
Page 47
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7b. Wetland Loss Measured by the
National Wetlands Inventory
1780s - 1980s
AnaKsis of Alaska and Hawaii
reserved for Phase 2
Watershed Gassification
| | Low Level of Wetland Loss
| | IVbderate Level of Wetland Loss
] High Level of Wetland Loss
Index of Watershed
Indicators
Source: U.S. Fish arel Wildlife Service
June 24, 1997
Ti 4-933SK
-------
Map7b
Importance of Wetland Loss Measured by the NWI
Wetlands have not always been recognized as important to aquatic system health. In
times past, they have been intentionally drained and filled as land was developed, and as
a result, loss of wetlands has been substantial. The result has been loss of habitat and loss
of watershed capacity for flood retention. This information shows the extent of the loss
of this resource since Colonial times, and is a measure of the long-standing resource
reduction that threatens streams and rivers today. The National Wetlands Inventory
plans, directs, coordinates, and monitors the gathering, analysis, dissemination, and
evaluation of information relating to the location, quantity, and ecological importance of
the Nation's wetlands.
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your Watershed"
at:
Click on the data layer of interest to find
documentation and FTP (File Transfer Protocol) addresses.
Description of the Data Layer
The data used in the National Wetlands Inventory (NWI), 1780s-1980s) provides
historical data from the U.S Fish and Wildlife Service on wetland acreage on federal and
non-federal lands. (State level)
Data Sufficiency Threshold
All available data were used.
Notes on Interpreting this Information
• Data Need to be Much More Consistent/Much Additional Data Needed
See "Plans to Improve this Data Layer" for details
• The historical NWI data were designed to track wetland change on a state-
wide basis and, in most cases, do not provide robust watershed information.
• Unlike the other 14 IWI data layers, these data are reported at the 6 digit
accounting unit scale (each 6 digit unit contains several 8 digit units), which
IWI interpolated to the 8 digit area.
• Since NWI data are reported by state, the loss estimated for watersheds lying
in two or more states may not reliably reflect the NWI historical data.
Plans to Improve this Data Layer
1. U.S. EPA is working towards reporting on both the quantity and quality of wetlands.
However, wetland biological monitoring programs are still in their infancy. As States
establish wetland monitoring programs and include this information in their 305(b)
reports, better data will be available for this data layer
2. U.S. EPA is continuing to work with the USFWS to monitor wetland loss and report
improvements in wetland acreage The Federal Geographic Data Committee Wetlands
Subcommittee (which includes U.S. EPA, USFWS, NRCS, and other federal agencies) is
exploring new approaches of tracking wetland acreage, reporting more frequently, and
reporting at the 8-digit watershed level
For More Information Contact:
Database Owners:
NWI: U.S. Fish and Wildlife Service (USFWS) Internet: http //www.nwi fws gov/
Individual Contacts:
NWI- Tom Dahl
E-mail: Tom_Dahl@mail.fws.gov
Phone: (813)570-5429
Data Source:
National Wetlands Inventory (NWI), 1780s-1980s
Additional Information
For information about wetlands, contact:
EPA Wetlands Information Hotline (contractoi operated)
1-800-832-7828 or httpV/www epa gov/OWOW/wetlands/wetline.html
For additional information about the wetlands data layer, contact:
Tom Danielson, U.S. Environmental Protection Agency, Wetlands Division
E-mail: Danielson.Tom@epamail epa gov Phone (202)260-5299
I'aec
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12a. Potential Pesticide Runoff
from Farm Fields
1990-1995
Analysis ot Alaska and
1 tmaii reserved t'cT Phase 2
Watershed Classification
| | Low Potential for Runoff
| | Moderate Potential for Runoff
| | High Potential for Runoff
gSS Insufficient IW1 Data
Index of Watershed
Indicators
Source: Natural Resources Conservation Sen ice
-------
Map 12a
Importance of Potential Pesticide Runoff from Farm Fields
Pesticide loss from farm fields is an important source of water quality
degradation in some watersheds. This indicator was developed to show which
watersheds have the greatest potential for the movement of agricultural pesticides
from farm fields through surface water runoff. The indicator represents potential loss
at the edge of the field based on the factors that are known to be important
determinants of pesticide loss, including: 1) soils characteristics, 2) historical
pesticide use, 3) chemical properties of the pesticides used, 4) annual rainfall and its
relationship to runoff, and 5) major field crops grown in 1992. Watersheds with high
scores have a greater risk of pesticide contamination of surface water than those with
low scores.
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your
Watershed" at: . Click on the data layer of
interest to find documentation and FTP (File Transfer Protocol) addresses.
Description of the Data Layer
Using national-level databases, a simulation was conducted of potential pesticide
losses from representative farm fields. About 170,000 Natural Resources Inventory
(NRI) sample points were treated as ''representative fields." Thirteen crops were
included in the simulation: barley, corn, cotton, oats, peanuts, potatoes, rice,
sorghum, soybeans, sugar beets, sunflowers, tobacco, and wheat. The potential for
pesticide loss from each "representative field" was estimated using the state average
pesticide application rate and percent acres treated from the National Pesticide Use
Database. The maximum percent runoff loss over a 20-year simulation of rainfall
from the Pesticide Loss Database was imputed to NRI sample points using
match-ups by soil properties and proximity to 55 climate stations. The total loss of
pesticides from each "representative field" was estimated by summing over the loss
estimates for all the pesticides that the National Pesticide Use Database reported for
each State and crop. Watershed scores were determined by averaging the scores for
the NRI sample points within each watershed
Data Sufficiency Thresholds
No data sufficiency threshold was applied.
Notes on Interpreting this Information
» Data Consistent/Sufficient Data Collected
See "Plans to Improve this Data Layer "for details.
• The indicator measures only the potential for pesticides to run off farm
fields, ft does not estimate actual pesticide loss
• Research has shown that pesticide loss from farm fields can be
substantially reduced by management practices that enhance the water
holding capacity and organic content of the soil and reduce water runoff.
Where these practices are being used, the potential loss measured by this
indicator will be over-estimated.
• Pesticide loss from farm fields does not always translate to water quality
impairment. Pesticides degrade during transport from the farm field to the
water body. Dilution by runoff from non-cropland areas in the watershed
will also reduce concentrations observed in surface water.
• The indicator does not include fruits, nuts, and vegetables. Watersheds
with large acreage of these crops will have a greater risk of water quality
contamination than shown by this indicator.
• Estimates using the NRI report conditions on non-federal rural lands. In
watersheds with significant Federal or Tribal lands not inventoried in the
NRI, estimates may not reflect the vulnerability accurately.
Plans to Improve this Data Layer
Research is underway to incorporate relative toxicity of the pesticides in the
aggregation scheme. The present indicator treats all pesticides as equally risky
to the environment, even though some pesticides have lower "safe" thresholds
than others.
For More Information Contact:
Database Owner
Natural Resources Conservation Service, U.S. Department of Agriculture
Individual Contact
Robert Kellogg, NRCS/USDA
E-mail: robert.kellogg@usda.gov
Phone: (202) 690-0341
Data Source:
1. National Resources Inventory
U.S. Dept. of Agriculture, National Resources Conservation Service,
1992
2. National Pesticide Use Database
Gianessi, Leonard P., and James Earl Anderson. Pesticide Use in U.S.
Crop Production: National Data Report. National Center for Food and
Agricultural Policy, Washington D.C., February 1995.
3. Pesticide Loss Database
Don W. Goss, Texas Agricultural Experiment Station, Temple, Texas
Page 5 I
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12b. Potential Nitrogen Runoff
from Farm Fields
1990 -1995
W
Analysis of Alaska and
Hawaii reserved for Phase 2
Watershed Classification
| | Low Potential for Runoff
| | Moderate Potential for Runoff
I | High Potential for Runoff
• Insufficient IWI Data
Index of Watershed
Indicators
Source: Natural Resources Conservation Service
June 22,1997
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Map 125
Importance of Potential Nitrogen Runoff from Farm Fields
Nitrogen runoff from farm fields can contribute to eutrophication of downstream
waterbodies and sometimes impair the use of surface water for drinking water purposes.
This indicator was developed to show which watersheds had the greatest potential for
agricultural sources of nitrogen loadings to surface water. It represents potential nitrogen
runoff at the edge of the field based on commercial fertilizer applications, uptake of
nitrogen by crops, potential nitrogen loadings from confined animal waste disposal, and
annual rainfall and its relationship to runoff. Watersheds with the highest scores have a
greater potential of significant nitrogen loadings from agricultural sources than
watersheds with low scores.
Access to Detailed Data:
Access to detailed data for each data layer is available through "Surf Your Watershed"
at: . Click on the data layer of interest to find
documentation and FTP (File Transfer Protocol) addresses.
Description of the Data Layer
This indicator is a composite of two separate indices: a vulnerability index for the
potential for commercial fertilizer to run off from farm fields, and an index of the runoff
potential for manure nitrogen. The nitrogen commercial fertilizer index was constructed
using the National Resources Inventory (NRI) as a modeling framework. About 160,000
NRI sample points were treated as "representative fields." Crops include corn, soybeans,
wheat, cotton, barley, rice, and sorghum. A per-acre estimate of pounds of nitrogen
available for runoff at the edge of field was calculated as the difference between the rate
of application per treated acre and the amount of nitrogen taken up by the harvestable
portion of the crop. The amount of nitrogen taken up by the harvestable portion of the
crop was estimated by multiplying the percent of nitrogen in the grain times the county
per-acre average yield for 1988-1992. The vulnerability index was constructed by
multiplying the per-acre amount of nitrogen available for runoff by a runoff factor for the
two months following planting for each "representative field." The runoff factor was
based on rainfall and the curve number method of estimating surface runoff from a field
The average vulnerability index for all "representative fields" in a watershed was used to
characterize the potential for commercial fertilizer to run off from farm fields.
The runoff potential for manure nitrogen per watershed was based on manure loadings
derived from confined livestock inventories reported in the 1992 Agriculture Census
database The total pounds of nitrogen in manure was multiplied by an average
12-month runoff factor for each watershed to create the index.
The composite indicator was constructed by ranking the two indexes and summing the
ranks for each watershed.
Data Sufficiency Thresholds
No data sufficiency threshold was applied.
Notes on Interpreting this Information
• Data Consistent/Sufficient Data Collected.
See "Plans to improve this Data Layer" for details.
• The indicator measures only the potential for nitrogen to run off farm fields It
does not estimate actual nitrogen runoff loss
• Farm management practices are not included in the determination of the
indicator. Research has shown that nitrogen loss can be substantially reduced
by careful timing of nitrogen applications and management practices that
reduce water runoff. Where these practices are being used, the potential loss
measured by this indicator will be over-estimated.
• Nitrogen loss from farm fields does not always translate to water quality
impairment. Dilution by runoff from non-cropland areas in the watershed will
reduce nitrogen concentrations observed in surface water.
• The index for commercial fertilizer applications only includes estimates for 7
crops. Watersheds with large acreage of other crops where commercial
nitrogen fertilizer is applied will have a greater risk oj water quality
contamination than shown by this indicator.
• Estimates of manure loadings are not adjusted for animal waste treatment
facilities (such as lagoons) although they are adjusted for storage losses and
volatilization of nitrogen during application Where animal waste treatment
facilities are used, the indicator will over-estimate manure loadings
• Estimates using the NRI represent non-federal rural lands. In watersheds with
significant Federal or Tribal lands not inventoried in the NRI, estimates may
not reflect the vulnerability accurately
Plans to Improve this Data Layer
Research is underway to more precisely estimate nitrogen loss from farm fields, and to
include additional crops.
For More Information Contact:
Database Owner:
U.S. Department of Agriculture, Natural Resources Conservation Service
Individual Contact:
Robert Kellogg, NRCS/USDA
E-mail- robert.kellogg@usdagov
Phone: (202) 690-0341
Data Source.
1. National Resources Inventory, U.S. Department of Agriculture, Natural Resources
Conservation Service, 1992
2 Nitrogen Use Statistics; U.S Department of Agriculture, Economic
Research Service
3 Crop Yield Data; U S. Department of Agriculture, National Agricultural Statistics
Service
4. Census of Agriculture, 1992, Bureau of the Census
Page 53
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12c. Sediment Delivery to Rivers and Streams
from Cropland and Pastureland
1990 -1995
vy
Analysis of Alaska and
Hawaii reservedfcr Phase 2
Watershed Classification
| | Low Potential for Delivery
[ | Ivfoderate Potential for Delivery
| | High Potential for Delivery
I Insufficient IWI Data
Index of Watershed
Indicators
Source: Nitural Resources Conservation Sen ice
-------
Map 12c
Importance of Sediment Delivery to Rivers and Streams
from Cropland and Pastureland
Soil eroding from agricultural land can be transported by water runoff to
rivers and streams and degrade the quality of surface water. Carried with
this soil is organic matter which also degrades the quality of streams, rivers,
and estuaries. The potential for soil erosion varies from watershed to
watershed depending on the extent of agricultural land in the watershed,
rainfall amounts and intensity, soil characteristics, landscape characteristics,
cropping patterns, and farm management practices. These factors were
included in a national-level simulation model that was used to estimate the
amount of sediment delivered to rivers and streams in each watershed. The
simulation estimated sheet and rill erosion; gully erosion was not included.
Access to Detailed Data
Access to detailed data for each data layer is available through "Surf Your
Watershed" at: Click on the data
layer of interest to find documentation and FTP (File Transfer Protocol)
addresses
Description of the Data Layer
The simulation was conducted as part of the Hydrologic Unit Modeling of
the United States (HUMUS) project, which incorporates several
national-level natural resource and land use databases and a variety of
process models in a Geographic Information System. The framework for
the national simulation consists of the 2,11 I hydrologic units in the 48
States. Each hydrologic unit is divided into subareas according to the major
land uses. Up to 14 subareas per watershed are available to represent
cropland and pastureland (7 irrigated, 7 nonirrigated). Soils characteristics
for each subarea are taken from the STATSGO soils database. A 30-year
weather database is available for each watershed. A process model
incorporating hydrology, weather, sedimentation, crop growth, and
agricultural management (SWAT-Soil and Water Assessment Tool) is
applied to each subarea to simulate the relationships among rainfall, runoff,
IcaclimR, groundwater return flow, farm management practices, erosion,
and surface flow in rivers and streams.
SWAT is a continuous time model that operates on a daily time step for
each of the 30 years of the weather database. One of the outputs of the
model is average annual sediment delivery to rivers and streams from sheet
and rill erosion from cropland and pastureland, as shown on this map.
Data Sufficiency Thresholds
No data sufficiency threshold was applied.
Notes on Interpreting this Information
• Data Consistent/Sufficient Data Collected
See "Plans to Improve this Data Layer for details.
• Sediment loads from nonagr(cultural land uses are not included in
these estimates. Estimates represent loadings delivered to rivers
and streams, and do not represent in-stream loads. Gully erosion
and channel erosion are also not included
Plans to Improve this Data Layer
The data and models used by HUMUS are continually updated and refined.
There are plans to improve sediment estimates by comparing model results
for in-stream loadings to actual loadings and adjusting the parameters of the
model where needed. HUMUS will also be expanded to estimate sediment
loadings from nonagricultural areas and other sources of erosion.
For More Information Contact:
Database Owner:
Texas Agricultural Experiment Station, Temple, Texas
Individual Contact
Clive Walker, Texas Agricultural Experiment Station, Temple, Texas
E-mail: walker@brcsunO.tamu.edu
Phone:(817)770-6655
Data Source:
HUMUS (Hydrologic Unit Modeling of the United States)
Page 55
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Contacts for Further Information
Many individuals and organizations contributed information to and review of the Index of Watershed Indicators, and we thank them all. It has been a pleasure working
with so many dedicated and knowledgeable partners. For further information or to answer questions you may have, there are many contacts, some of which we list
below.
Surf Your Watershed:
As a first step to answer questions, we urge you if possible to go to the Internet program "Surf Your Watershed" at http://www.epa.gov/surf. Surf provides additional
information about each watershed in the Index of Watershed Indicators, individual contacts for particular kinds of data, more detailed background data (such as lists of
the specific fish advisories in effect in the watershed) and also links to much information in addition to the 15 indicators we used for the Index of Watershed Indicators
Internet also allows us to easily provide updated information in a way not possible in a published paper product. For further information on "Surf call Karen Klima at
(202) 260-7087 (E-mail KIima.Karen@epamail.epa.gov)
If you do not find the information you need on "Surf Your Watershed," you can call the following:
The Index of Watershed Indicators process:
Sarah Lehmann at EPA Headquarters on 202 260-7021 (E-MAIL Lehjnann.Sarah@epamail.epa.gov)
Index of Watershed Indicators.
o Overall assessment of data: Charles Spooner, EPA Headquarters on (202) 260-1314 (E-MAIL Spooner.Charles@epamail.epa.gov)
o Contacts for each indicator are listed on the individual maps
Monitoring Information:
Call 202 260-7040 and ask for the Monitoring Publications List.
Regional Contacts: Each EPA region has an Index of Watershed Indicators contact who can answer your questions or direct you to the right source:
Region I: Irish Garrigan 617 565-4728 Region 2: Larry Rinaldo 212637-3820 Region 3: Stuart Kerzner 215566-5709
CT, ME, MA, NH, RJ, VT NJ, NY, PR, VI DE, DC, MD, PA, VA, WV
Region 4: David Melgaard 404562-9265 Region 5: Tim Henry 312 886-6107 Region 6: Charlie Howell 214665-8354
AL, FL, GA, KY, MS, NC, SC, TN IL, IN, MI, MN, OH, WI AR, LA, NM, OK, TX
Region 7: Julie Elfving 913551-7475 Region 8: Jill Minter 303 312-6084 Region 9: Janet Hashimoto 415744-1933
IA, KS, MO, NE CO, MT, ND, SD, UT, WY AZ, CA, HI, NV, AS, GU
Region 10: Pat Cirone 206 553-1597
AK, ID, OR, WA
Page 56
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