Appendix III

Appendix III

Use Support Methodology
and
Use Support Ratings

Appendices

Introduction to Use Support

All surface waters of the state are assigned a classification appropriate to the best-intended uses
of that water. Waters are assessed to determine how well they are meeting the classified or best-
intended uses. The assessment results in a use support rating for the use categories that apply to
that water.

Use Support Categories

Beginning in 2000 with the Roanoke River Basinwide Water Quality Plan, DWQ assesses
ecosystem health and human health risk through the use of five use support categories: aquatic
life, recreation, fish consumption, water supply, and shellfish harvesting. These categories are
tied to the uses associated with the primary classifications applied to NC rivers and streams.
Waters are Supporting if data and information used to assign a use support rating meet the
criteria for that use category. If these criteria are not met, then the waters are Impaired. Waters
with inconclusive data and information are Not Rated. Waters where no data or information are
available to make an assessment are No Data. The table below specifies which use support
categories apply to which primary classifications.

A single water may have more than one use support rating corresponding to one or more of the
use support categories, as shown in the following table. For many waters, a use support category
will not be applicable (N/A) to the classification of that water (e.g., shellfish harvesting is only
applied to Class SA waters). A full description of the classifications is available in the DWQ
document titled: Classifications and Water Quality Standards Applicable to Surface Waters of
North Carolina (15A NCAC 2b .0100 and .0200). Information can also be found at
http://h2o.enr.state.nc.us/wqs/.

Use Support Categories

Primary
Classification
Ecosystem
Approach
Human Health
Approach
Aquatic
Life
Fish
Consumption Recreation Water
Supply
Shellfish
Harvesting
C X X X N/A N/A
SC X X X N/A N/A
B X X X N/A N/A
SB X X X N/A N/A
SA X X X N/A X
WS I – WS IV X X X X N/A

Assessment Period

Data and information are used to assess water quality and assign use support ratings using a five-
year data window that ends on August 31 of the year of basinwide biological sampling. For
example, if biological data are collected in a basin in 2004, then the five-year data window for
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use support assessments would be September 1, 1999 to August 31, 2004. There are
occasionally some exceptions to this data window, especially when follow up monitoring is
needed to make decisions on samples collected in the last year of the assessment period.

Assessment Units

DWQ identifies waters by index numbers and assessment unit numbers (AU). The AU is used to
track defined stream segments or waterbodies in the water quality assessment database, for the
303(d) Impaired waters list, and in the various tables in basin plans and other water quality
documents. The AU is a subset of the DWQ index number (classification identification number).
A letter attached to the end of the AU indicates that the AU is smaller than the DWQ index
segment. No letter indicates that the AU and the DWQ index segment are the same.

Interpretation of Data and Information

When interpreting the use support ratings, it is important to understand the associated limitations
and degree of uncertainty. Although these use support methods are used for analyzing data and
information and determining use support ratings, best professional judgment is applied during
these assessments. Use support ratings are intended to provide an assessment of water quality
using a five-year data window, to describe how well surface waters support their classified uses,
and to document the potential stressors contributing to water quality degradation and the sources
of these contributions.

Use support methods continue to improve over time, and the information and technology used to
make use support determinations also continue to become more accurate and comprehensive.
These improvements sometimes make it difficult to make generalizations comparing water
quality between basin plans. However, technology and methods improvements result in more
scientifically sound use support assessments.

Assessment Methodology

Introduction

Many types of data and information are used to determine use support ratings and to identify
stressors and sources of water quality degradation. All existing data pertaining to a stream
segment for each applicable use support category are entered into a use support database and
may include its use support ratings, basis of assessment, biological and ambient monitoring data,
stressors and potential sources. Data used in the use support assessments include biological data,
chemical/physical data, lakes assessment data, fish consumption advisories from the NC
Department of Health and Human Services, swimming advisories and shellfish sanitation
growing area classifications from the NC Division of Environmental Health (as appropriate), and
available land cover and land use information.

The following describes the data and methodologies used to conduct use support assessments.
These methods will continue to be refined as additional information and technology become
available.
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Basis of Assessment

Assessments are made on an overall basis of either monitored (M) or evaluated (E), depending
on the level of information available. A monitored rating is based on the most recent five-year
data window and site-specific data and is therefore treated with more confidence than an
evaluated rating.

Rating
Basis
Use Support
Category
Assessment
Applicability*
S/M AL Biological community data or ambient water quality parameters do not exceed criteria in
AU during assessment period. Biological and ambient data are independently applied.
S/M REC Ambient fecal bacteria parameter does not exceed criteria in AU or AU with RECMON
sites is posted with advisories for 61 days or less during assessment period.
S/M FC AU does not have site-specific advisory and is not under a mercury advice or drains to
areas within a mercury advice, or fish tissue data do not exceed criteria.
S/M SH AU is a DEH Approved shellfish growing area.

I/M AL Biological community data or ambient water quality parameters exceed criteria in AU
during assessment period. Biological and ambient data are independently applied.
I/M REC Ambient fecal bacteria parameter exceeds criteria in AU or AU with RECMON sites is
posted with advisories for more than 61 days during assessment period.
I/M FC Fish tissue data collected in AU during assessment period and basin are under mercury
advice or site-specific advisory.
I/M SH AU is a DEH Conditionally-Approved, Prohibited or Restricted shellfish growing area.

NR/M AL Biological community is Not Rated or inconclusive, or ambient water quality parameters
are inconclusive in AU during assessment period. Biological and ambient data are
independently applied.
NR/M REC Ambient fecal bacteria parameter exceeds annual screening criteria, but does not exceed
assessment criteria of five samples in 30 days in AU during assessment period.
S/E AL AU is a tributary to a S/M AU and land use is similar between AUs.
S/E WS AU is classified as WS, and DEH report notes no significant closures at time of
assessment.

I/E FC AU is in basin under a mercury advice or drains to areas within a mercury advice and has
no fish tissue data.

NR/E AL AU is tributary to I/M AU, or AU is in watershed with widespread and changing land
use, or other information suggests negative water quality impacts to AU. Discharger in
AU has noncompliance permit violations or has failed three or more WET tests during
the last two years of the assessment period.
NR/E REC Discharger has noncompliance permit violations of fecal bacteria parameter during last
two years of assessment period.

ND AL, REC,
FC, SH
No data available in AU during assessment period.
Note: S/M = Supporting/Monitored I/M = Impaired/Monitored NR/M = Not Rated/Monitored
S/E = Supporting/Evaluated I/E = Impaired/Evaluated NR/E = Not Rated/Evaluated
ND = No Data
AL = Aquatic Life REC = Recreation FC = Fish Consumption
SH = Shellfish Harvesting WS = Water Supply
AU = Assessment Unit WET = Whole Effluent Toxicity
DEH = Division of Environmental Health * = for lakes assessments
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Supporting ratings are extrapolated up tributaries from monitored streams when there are no
problematic dischargers with permit violations or changes in land use/cover. Supporting ratings
may also be applied to unmonitored tributaries where there is little land disturbance (e.g.,
national forests and wildlife refuges, wilderness areas or state natural areas). Problem stressors
or sources (except general NPS) are not generally applied to unmonitored tributaries. Impaired
ratings are not extrapolated to unmonitored tributaries.

Stressors

Biological and ambient samplings are useful tools to assess water quality. However, biological
sampling does not typically identify the causes of impairment, and ambient sampling does not
always link water quality standards to a biological response. Linking the causes of impairment
and the biological response are a complex process (USEPA, 2000) that begins with an evaluation
of physical, chemical or biological entities that can induce an adverse biological response. These
entities are referred to as stressors. A stressor may have a measurable impact to aquatic health.
Not all streams will have a primary stressor or cause of impairment. A single stressor may not
be sufficient to cause impairment, but the accumulation of several stressors may result in
impairment. In either case, impairment is likely to continue if the stressor or the various
cumulative stressors are not addressed. Use support assessments evaluate the available
information related to potential stressors impacting water quality.

A stressor identification process may be initiated after a stream appears on the 303(d) list in
order to address streams that are Impaired based on biological data. Intensive studies are
required to summarize and evaluate potential stressors to determine if there is evidence that a
particular stressor plays a substantial role in causing the biological impacts. Intensive studies
consider lines of evidence that include benthic macroinvertebrate and fish community data,
habitat and riparian area assessment, chemistry and toxicity data, and information on watershed
history, current watershed activities and land uses, and pollutant sources. These studies result in
decisions regarding the probable stressors contributing to or causing impairment. The intensity
of a stressor study may be limited due to a lack of resources. In these cases, it may still be
appropriate to include stressors in use support assessments, but to also note where additional
information is needed in order to evaluate other stressors.

Where an ambient parameter is identified as a potential concern, the parameter is noted in the
DWQ database and use support summary table. Where habitat degradation is identified as a
stressor, DWQ and others attempt to identify the type of habitat degradation (e.g., sedimentation,
loss of woody habitat, loss of pools or riffles, channelization, lack of riparian vegetation,
streambed scour and bank erosion). Habitat evaluation methods are being developed to better
identify specific types of habitat degradation.

Aquatic Life Category

The aquatic life category is an ecosystem approach to assessing the biological integrity of all
surface waters of the state. The biological community data and ambient water quality data are
used in making assessments in this category. These represent the most important monitoring
data for making water quality assessments in the aquatic life category. Evaluation information
such as compliance and whole effluent toxicity information from NPDES dischargers, land
cover, and other more anecdotal information are also used to identify potential problems and to
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refine assessments based on the monitoring data. The following is a description of each
monitoring data type and the criteria used in assigning use support ratings. Criteria used to
evaluate the other information and assign use support ratings are also described. Refer to page
14 for lakes and reservoir assessment methods as applied in the aquatic life category.

Biological Data

Benthic macroinvertebrate (aquatic insects) community and fish community samples are the best
way to assess the biological integrity of most waterbodies. Unfortunately, these community
measures cannot be applied to every stream size and are further limited by geographic region.
These community measures are designed to detect current water quality and water quality
changes that may be occurring in the watershed. However, they are only directly applied to the
assessment unit where the sample was collected.

Where recent data for both benthic macroinvertebrates and fish communities are available, both
are evaluated for use support assessments. When two biological monitoring data types conflict,
best professional judgment is used to determine an appropriate use support rating. Where both
ambient monitoring data and biological data are available, biological data may be given greater
weight; however, each data type is assessed independently.

Benthic Macroinvertebrate Criteria

Criteria have been developed to assign bioclassifications to most benthic macroinvertebrate
samples based on the number of taxa present in the pollution intolerant aquatic insect groups of
Ephemeroptera, Plecoptera and Trichoptera (EPTs); and the Biotic Index (BI), which
summarizes tolerance data for all taxa in each sample. Because these data represent water
quality conditions with a high degree of confidence, use support ratings using these data are
considered monitored.

If a Fair macroinvertebrate bioclassification is obtained under conditions (such as drought or
flood conditions, recent spills, etc.) that may not represent normal conditions or is borderline Fair
(almost Good-Fair), a second sample should be taken within 12-24 months to validate the Fair
bioclassification. Such sites will not be Not Rated until the second sample is obtained.

Use support ratings are assigned to assessment units using benthic macroinvertebrate
bioclassifications as follows.

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Waterbody Sample
Type or Criteria Bioclassification Use Support
Rating
Mountain, piedmont, coastal A Excellent Supporting
Mountain, piedmont, coastal A Good Supporting
Swamp1 Natural Supporting
Mountain, piedmont, coastal A Good-Fair Supporting
Smaller than criteria but Good-Fair2 Not Impaired Supporting
Swamp1 Moderate Stress Supporting
Mountain, piedmont, coastal A Fair Impaired
Swamp1 Severe Stress Impaired
Mountain, piedmont, coastal A Poor Impaired
Criteria not appropriate to assign bioclassification Not Rated Not Rated
1 Swamp streams for benthos sampling are defined as streams in the coastal plain that have no visible flow for a part of the year,
but do have flow during the February to early March benthic index period.
2 This designation may be used for flowing waters that are too small to be assigned a bioclassification (less than three square
miles drainage area), but have a Good-Fair or higher bioclassification using the standard qualitative and EPT criteria.

Fish Community Criteria

The North Carolina Index of Biotic Integrity (NCIBI) is a method for assessing a stream’s
biological integrity by examining the structure and health of its fish community. The NCIBI
incorporates information about species richness and composition, indicator species, trophic
function, abundance and condition, and reproductive function. Because these data represent
water quality conditions with a high degree of confidence, use support ratings using these data
are considered monitored. Use support ratings are assigned to assessment units using the NCIBI
bioclassifications as follows:

NCIBI Use Support Rating
Excellent Supporting
Good Supporting
Good-Fair Supporting
Fair Impaired
Poor Impaired

If a Fair macroinvertebrate bioclassification is obtained under conditions (such as drought or
flood conditions, recent spills, etc.) that may not represent normal conditions or is borderline Fair
(almost Good-Fair), a second sample should be taken within 12-24 months to validate the Fair
bioclassification. Such sites will not be given a use support rating until validation is obtained.

The NCIBI was recently revised (NCDENR, 2001), and the bioclassifications and criteria have
also been recalibrated against regional reference site data (NCDENR, 2000a, 2000b and 2001a).
NCIBI criteria are applicable only to wadeable streams in the following river basins: Broad,
Catawba, Savannah, Yadkin-Pee Dee, Cape Fear, Neuse, Roanoke, Tar-Pamlico, French Broad,
Hiwassee, Little Tennessee, New and Watauga. Additionally, the NCIBI criteria are only
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applicable to streams in the piedmont portion of the Cape Fear, Neuse, Roanoke and Tar-Pamlico
River basins. The definition of "piedmont" for these four river basins is based upon a map of
North Carolina watersheds (Fels, 1997). Specifically:

In the Cape Fear River basin -- all waters except for those draining the Sandhills in Moore,
Lee and Harnett counties, and the entire basin upstream of Lillington, NC.
•
•
•
•
In the Neuse River basin -- the entire basin above Smithfield and Wilson, except for the
south and southwest portions of Johnston County and eastern two-thirds of Wilson County.
In the Roanoke River basin -- the entire basin in North Carolina upstream of Roanoke
Rapids, NC and a small area between Roanoke Rapids and Halifax, NC.
In the Tar-Pamlico River basin -- the entire basin above Rocky Mount, except for the lower
southeastern one-half of Halifax County and the extreme eastern portion of Nash County.

NCIBI criteria have not been developed for:

• Streams in the Broad, Catawba, Yadkin-Pee Dee, Savannah, French Broad, Hiwassee, Little
Tennessee, New and Watauga River basins which are characterized as wadeable first to third
order streams with small watersheds, naturally low fish species diversity, coldwater
temperatures, and high gradient plunge-pool flows. Such streams are typically thought of as
"Southern Appalachian Trout Streams".
• Wadeable streams in the Sandhills ecoregion of the Cape Fear, Lumber and Yadkin-Pee Dee
River basins.
• Wadeable streams and swamps in the coastal plain region of the Cape Fear, Chowan,
Lumber, Neuse, Pasquotank, Roanoke, Tar-Pamlico and White Oak River basins.
• All nonwadeable and large streams and rivers throughout the state.

Ambient Water Quality Monitoring Criteria

Chemical/physical water quality data are collected through the DWQ Ambient Monitoring
Program statewide and NPDES discharger coalitions in some basins. All samples collected
(usually monthly) during the five-year assessment period are used to assign a use support rating.
Ambient water quality data are not direct measures of biological integrity, but the
chemical/physical parameters collected can provide an indication of conditions that may be
impacting aquatic life. Because these data represent water quality conditions with a high degree
of confidence, use support ratings assigned using these data are considered monitored. Where
both ambient data and biological data are available, each data type is assessed independently.

The parameters used to assess water quality in the aquatic life category include dissolved
oxygen, pH, chlorophyll a and turbidity. Criteria for assigning use support ratings to assessment
units with ambient water quality data of a minimum of ten samples are as follows:

Ratings Criteria Rating
Numerical standard exceeded in ≤10% of samples Supporting
Numerical standard exceeded in >10% of samples Impaired
Less than 10 samples collected Not Rated
DO and pH standard exceeded in swamp streams Not Rated

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Multiple Monitoring Sites

There are assessment units with more than one type of monitoring data. When the data from
multiple biological data types are not in agreement, best professional judgment is used to assign
a bioclassification and use support rating for that assessment unit. Biological monitoring is
typically assessed independent of ambient monitoring data and either may be used to assign a use
support rating for an assessment unit. Monitoring data are always used over the evaluation
information; however, evaluation information can be used to lengthen or shorten monitored
assessment units and to assign use support ratings on an evaluated basis to non-monitored
assessment units.

NPDES Wastewater Whole Effluent Toxicity (WET) Information

Whole Effluent Toxicity (WET) tests are required for all major NPDES discharge permit
holders, as well as those minor NPDES dischargers with complex effluent (defined as not being
of 100 percent domestic waste). WET tests are evaluated to determine if the discharge could be
having negative water quality impacts. If a stream with a WET test facility has not been sampled
for instream chronic toxicity, biological community data or has no ambient water quality data,
and that facility has failed three or more WET tests in the last two years of the assessment
period, the assessment unit is Not Rated. Because this information is not a direct measure of
water quality and the confidence is not as high as for monitoring data, this use support rating is
considered evaluated rather than monitored. Problems associated with WET test failures are
addressed through NPDES permits.

NPDES Discharger Daily Monitoring Report Information

NPDES effluent data monthly averages of water quality parameters are screened for the last two
years of the assessment period. If facilities exceed the effluent limits by 20 percent for two or
more months during two consecutive quarters, or have chronic exceedances of permit limits for
four or more months during two consecutive quarters, then the assessment unit is Not Rated if no
biological or ambient monitoring data are available. If biological or ambient data are available,
that data will be used to develop a use support rating for appropriate stream segments. Because
this information is not a direct measure of water quality and the confidence is not as high as for
monitoring data, this use support rating is considered evaluated rather than monitored.

Fish Consumption Category

The fish consumption category is a human health approach to assess whether humans can safely
consume fish from a waterbody. This category is applied to all waters of the state. The use
support rating is assigned using fish consumption advisories or advice as issued by the NC
Department of Health and Human Services (NCDHHS). The fish consumption category is
different from other categories in that assessments are based on the existence of a DHHS fish
consumption advice or advisory at the time of assessment. The advice and advisories are based
on DHHS epidemiological studies and on DWQ fish tissue data, so a fish tissue monitoring site
will constitute a monitored assessment unit (AU) and all other AUs will be evaluated. DWQ
fish tissue data are used to inform DHHS of potential fish tissue toxicity. DHHS is responsible
for proclaiming a fish tissue advisory for any waterbody. Fish tissue monitoring data are not
used directly for assigning a use support rating in this category.
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If a limited site-specific fish consumption advisory or a no consumption advisory is posted at the
time of assessment, the water is Impaired. If there are no site-specific advisories posted or the
stream is not in a basin where mercury advice is applied, then the assessment unit will be
Supporting in this category.
The NCDHHS has developed regional fish consumption advice (all waters south and east of I-
85) for certain fish species shown to have elevated levels of mercury in their tissue. DWQ
applies the DHHS fish consumption advice for mercury on a basinwide scale rather than an AU
scale in recognition that fish move up and downstream regardless of the presence of I-85. All
AUs draining below or intersecting I-85 are Impaired in the fish consumption category. AUs
with monitoring data are considered Impaired/Monitored, and AUs with no monitoring data are
considered Impaired/Evaluated. When a DHHS site-specific advisory is in place for a parameter
other than mercury, the assessment is based on that advisory and the mercury advice will take a
lower ranking in the assessment. Therefore, when a site-specific advisory is in place in a basin
with a mercury advice and the AU has fish tissue monitoring data, the AU will be considered
Impaired/Monitored for the specific parameter, rather than Impaired/Evaluated for mercury.

Basins under the mercury advice are the Cape Fear, Chowan, Lumber, Neuse, Pasquotank,
Roanoke, White Oak and Yadkin-Pee Dee. All waters in these basins are Impaired in the fish
consumption category, even when there is a site-specific advisory. All waters are also
considered Monitored or Evaluated, dependent upon the availability of monitoring data.

Only a small portion of the Catawba River basin is intersected by I-85 (lower Mecklenberg,
Union and Gaston counties). Due to the presence of dams that impede fish travel throughout the
Catawba River basin, only those waters draining to and entering the mainstem Catawba below I-
85 and are not impeded by dams are considered Impaired/Evaluated.
Basins not under the mercury advice are the Broad, French Broad, Hiwassee, Little Tennessee,
New, Savannah and Watauga. All waters in these basins are Supporting the fish consumption
category if there is no site-specific advisory; waters are Impaired if there is a site-specific
advisory. All waters are also considered Monitored or Evaluated, dependent upon the
availability of monitoring data.
In order to separate this regional advice from other fish consumption advisories and to identify
actual fish populations with high levels of mercury, only waters with fish tissue monitoring data
are presented on the use support maps.

Recreation Category

This human health related category evaluates waters for the support of primary recreation
activities such as swimming, water-skiing, skin diving, and similar uses usually involving human
body contact with water where such activities take place in an organized manner or on a frequent
basis. Waters of the state designated for these uses are classified as Class B, SB and SA. This
category also evaluates other waters used for secondary recreation activities such as wading,
boating, and other uses not involving human body contact with water, and activities involving
human body contact with water where such activities take place on an infrequent, unorganized or
incidental basis. Waters of the state designated for these uses are classified as Class C, SC and
WS.
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The use support ratings applied to this category are currently based on the North Carolina fecal
coliform bacteria water quality standard where ambient monitoring data are available or on the
duration of local or state health agencies posted swimming advisories. Use support ratings for
the recreation category may be based on other bacteriological indicators and standards in the
future.

DWQ conducts monthly ambient water quality monitoring that includes fecal coliform bacteria
testing. The Division of Environmental Health (DEH) tests coastal recreation waters (beaches)
for bacteria levels to assess the relative safety of these waters for swimming. If an area has
elevated bacteria levels, health officials will advise that people not swim in the area by posting a
swimming advisory and by notifying the local media and county health department.

The North Carolina fecal coliform bacteria standard for freshwater is: 1) not to exceed the
geometric mean of 200 colonies per 100 ml of at least five samples over a 30-day period; and 2)
not to exceed 400 colonies per 100 ml in more than 20 percent of the samples during the same
period. The AU being assessed for the five-year data window is Supporting in the recreation
category if neither number (1) nor (2) of the standard are exceeded. The AU being assessed is
Impaired in the recreation category if either number (1) or (2) is exceeded. Waters without
sufficient fecal coliform data are Not Rated, and waters with no data are noted as having No
Data.

Assessing the water quality standard requires significant sampling efforts beyond the monthly
ambient monitoring sampling and must include at least five samples over a 30-day period.
Decades of monitoring have demonstrated that bacteria concentrations may fluctuate widely in
surface waters over a period of time. Thus, multiple samples over a 30-day period are needed to
evaluate waters against the North Carolina water quality standard for recreational use support.
Waters classified as Class SA, SB and B are targeted for this extra sampling effort due to the
greater potential for human body contact. Therefore, some waters will be Not Rated in this
category based on a DWQ yearly screening of all waters where an AU is above 200 colonies per
100 ml, or more than 20 percent of samples are above 400 colonies per 100 ml, and where the
extra sampling effort has not been conducted.

Waters with beach monitoring sites will be Impaired if the area is posted with an advisory for
greater than 61 days of the assessment period. Waters with beach monitoring sites with
advisories posted less than 61 days will be Supporting. Other information can be used to Not
Rate unmonitored waters.

DWQ Ambient Monitoring Fecal Coliform Screening Criteria

As with other information sources, all available information and data are evaluated for the
recreation category using the assessment period. However, DWQ conducts an annual screening
of DWQ ambient fecal coliform data to assess the need for additional monitoring or immediate
action by local or state health agencies to protect public health.

Each March, DWQ staff will review bacteria data collections from ambient monitoring stations
statewide for the previous sampling year. Locations with annual geometric means greater than
200 colonies per 100 ml, or when more than 20 percent of the samples are greater than 400
colonies per 100 ml, are identified for potential follow-up monitoring conducted five times
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within 30 days as specified by the state fecal coliform bacteria standard. If bacteria
concentrations exceed either portion of the state standard, the data are sent to DEH and the local
county health director to determine the need for posting swimming advisories. DWQ regional
offices will also be notified.

Due to limited resources and the higher risk to human health, primary recreation waters (Class B,
SB and SA) will be given monitoring priority for an additional five times within 30 days
sampling. Follow-up water quality sampling for Class C waters will be performed as resources
permit. Any waters on the 303(d) list of Impaired waters for fecal coliform will receive a low
priority for additional monitoring because these waters will be further assessed for TMDL
development.

DWQ attempts to determine if there are any swimming areas monitored by state, county or local
health departments or by DEH. Each January, DEH, county or local health departments are
asked to list those waters which were posted with swimming advisories in the previous year.

Shellfish Harvesting Use Support

The shellfish harvesting use support category is a human health approach to assess whether
shellfish can be commercially harvested and is therefore applied only to Class SA waters. The
following data sources are used to assign use support ratings for shellfish waters.

Division of Environmental Health (DEH) Shellfish Sanitation Surveys

DEH is required to classify all shellfish growing areas as to their suitability for shellfish
harvesting. Estuarine waters are delineated according to DEH shellfish management areas (e.g.,
Outer Banks, Area H-5) which include Class SA, SB and SC waters. DEH samples growing
areas regularly and reevaluates the areas by conducting shellfish sanitation surveys every three
years to determine if their classification is still applicable. DEH classifications may be changed
after the most recent sanitary survey. Classifications are based on DEH bacteria sampling,
locations of pollution sources, and the availability of the shellfish resource. Growing waters are
classified as follows.

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DEH
Classification
DEH
Criteria
Approved
(APP)
Fecal Coliform Standard for Systematic Random Sampling:
The median fecal coliform Most Probable Number (MPN) or the geometric mean MPN of
the water shall not exceed 14 per 100 milliliters (ml), and the estimated 90th percentile
shall not exceed an MPN of 43 MPN per 100 ml for a 5-tube decimal dilution test.

Fecal Coliform Standard for Adverse Pollution Conditions Sampling:
The median fecal coliform or geometric mean MPN of the water shall not exceed 14 per
100 ml, and not more than 10 percent of the samples shall exceed 43 MPN per 100 ml for
a 5-tube decimal dilution test.
Conditionally
Approved-Open
(CAO)
Sanitary Survey indicates an area can meet approved area criteria for a reasonable period
of time, and the pollutant event is known and predictable and can be managed by a plan.
These areas tend to be open more frequently than closed.
Conditionally
Approved-Closed
(CAC)
Sanitary Survey indicates an area can meet approved area criteria for a reasonable period
of time, and the pollutant event is known and predictable and can be managed by a plan.
These areas tend to be closed more frequently than open.
Restricted
(RES)
Sanitary Survey indicates limited degree of pollution, and the area is not contaminated to
the extent that consumption of shellfish could be hazardous after controlled depuration or
relaying.
Prohibited
(PRO)
No Sanitary Survey; point source discharges; marinas; data do not meet criteria for
Approved, Conditionally Approved or Restricted Classification.

Assigning Use Support Ratings to Shellfish Harvesting Waters (Class SA)

DWQ use support ratings may be assigned to separate segments within DEH management areas.
In assessing use support, the DEH classifications and management strategies are only applicable
to DWQ Class SA (shellfish harvesting) waters. It is important to note that DEH classifies all
actual and potential growing areas (which includes all saltwater and brackish water areas) for
their suitability for shellfish harvesting. This will result in a difference of acreage between DEH
areas classified as CAC, PRO and RES, and DWQ waters rated as Impaired. For example, if
DEH classifies a 20-acre area CAC, but only 10 acres are Class SA, only those 10 acres of Class
SA waters are rated as Impaired.

The DEH "Closed" polygon coverage includes CAC, RES and PRO classifications, and it is not
currently possible to separate out the PRO from the RES areas. Therefore, these areas are a
combined polygon coverage, and DWQ rates these waters as Impaired.

Sources of fecal coliform bacteria are more difficult to separate out for Class SA areas. DEH
describes the potential sources in the sanitary surveys, but they do not describe specific areas
affected by these sources. Therefore, in the past, DEH identified the same sources for all Class
SA sections of an entire management area (e.g., urban runoff and septic systems). Until a better
way to pinpoint sources is developed, this information will continue to be used. A point source
discharge is only listed as a potential source when NPDES permit limits are exceeded.

DWQ and DEH are developing the database and expertise necessary to assess shellfish
harvesting frequency of closures. In the interim, DWQ has been identifying the frequency of
closures in Class SA waters using an interim methodology based on existing databases and GIS
A-III-12

shapefiles. There will be changes in reported acreages in future assessments using the permanent
methods and tools that result from this project.

Past Interim Frequency of Closure-Based Assessment Methodology

The interim method was used for the 2001 White Oak, 2002 Neuse and 2003 Lumber River
basin use support assessments. Shellfish harvesting use support ratings for Class SA waters
using the interim methodology are summarized below.

Percent of Time Closed
within Basin Data Window
DEH
Growing Area Classification
DWQ
Use Support Rating
N/A Approved* Supporting
Closed ≤10% of data window Portion of CAO closed ≤10% of data window Supporting
Closed >10% of the data window Portion of CAO closed >10% of data window Impaired
N/A CAC and PRO/RES** Impaired
* Approved waters are closed only during extreme meteorological events (hurricanes).
** CAC and P/R waters are rarely opened to shellfish harvesting.

For CAO areas, DWQ worked with DEH to determine the number of days and acreages that
CAO Class SA waters were closed to shellfish harvesting during the assessment period. For
each growing area with CAO Class SA waters, DEH and DWQ defined subareas within the CAO
area that were opened and closed at the same time. The number of days these CAO areas were
closed was determined using DEH proclamation summary sheets and the original proclamations.

The number of days that APP areas in the growing area were closed due to preemptive closures
because of named storms was not counted. For example, all waters in growing area E-9 were
preemptively closed for Hurricane Fran on September 5, 1996. APP waters were reopened
September 20, 1996. Nelson Bay (CAO) was reopened September 30, 1996. This area was
considered closed for ten days after the APP waters were reopened.

Current Assessment Methodology

Use support assessment for the 2005 Cape Fear River basin will be conducted such that only the
DEH classification will be used to assign a use support rating. By definition, CAO areas are
areas that DEH has determined do not, or likely do not, meet water quality standards and these
areas will be rated Impaired, along with CAC and PRO/RES areas. Only APP areas will be rated
Supporting.

Growing areas that have been reclassified by DEH during the assessment period from a lower
classification to APP will be rated Supporting. Areas that are reclassified from APP to any other
classification during the assessment period will be rated Impaired.

Over the next few years, DWQ, DEH, Division of Coastal Management (DCM) and Division of
Marine Fisheries (DMF) will be engaged in developing a fully functionally database with related
georeferenced (GIS) shellfish harvesting areas. The new database and GIS tools will be valuable
for the above agencies to continue to work together to better serve the public. Using the new
A-III-13

database with georeferenced areas and monitoring sites, DEH will be able to report the number
of days each area was closed excluding closures related to named storms.

Water Supply Use Support

This human health related use support category is used to assess all Class WS waters for the
ability of water suppliers to provide potable drinking water. Many drinking water supplies in NC
are drawn from human-made reservoirs that often have multiple uses.

Water supply use support is assessed using information from the seven DEH regional water
treatment plant (WTP) consultants. Each January, the WTP consultants are asked to submit a
spreadsheet listing closures and water intake switch-overs for all water treatment plants in their
region. This spreadsheet describes the length and time of the event, contact information for the
WTP, and the reason for the closure or switch.

The WTP consultants’ spreadsheets are reviewed to determine if any closures/switches were due
to water quality concerns. Those closures/switches due to water quantity problems and reservoir
turnovers are not considered for use support. The frequency and duration of closures/switches
due to water quality concerns are considered when assessing use support. In general, North
Carolina’s surface water supplies are currently rated Supporting on an Evaluated basis. Specific
criteria for rating waters Impaired are yet to be determined.

Use of Outside Data

DWQ actively solicits outside data and information in the year before biological sampling in a
particular basin. The solicitation allows approximately 60 days for data to be submitted. Data
from sources outside DWQ are screened for data quality and quantity. If data are of sufficient
quality and quantity, they may be incorporated into use support assessments. A minimum of ten
samples for more than a one-year period is needed to be considered for use support assessments.

The way the solicited data are used depends on the degree of quality assurance and quality
control of the collection and analysis of the data as detailed in the 303(d) report and shown in the
table below. Level 1 data can be use with the same confidence as DWQ data to determine use
support ratings. Level 2 or Level 3 data may be used to help identify causes of pollution and
stressors. They may also be used to limit the extrapolation of use support ratings up or down a
stream segment from a DWQ monitoring location. Where outside data indicate a potential
problem, DWQ evaluates the existing DWQ biological and ambient monitoring site locations for
adjustment as appropriate.

A-III-14

Criteria Levels for Use of Outside Data in Use Support Assessments
Criteria Level 1 Level 2 Level 3
Monitoring frequency of at least 10 samples for
more than a one-year period Yes Yes/No No
Monitoring locations appropriately sited and
mapped Yes Yes No
State certified laboratory used for analysis
according to 15A NCAC 2B .0103 Yes Yes/No No
Quality assurance plan available describing
sample collection and handling
Yes, rigorous
scrutiny Yes/No No

Lakes and Reservoir Use Assessment

Like streams, lakes are classified for a variety of uses. All lakes monitored as part of North
Carolina’s Ambient Lakes Monitoring Program carry the Class C (aquatic life) classification,
and most are classified Class B and SB (recreation) and WS-I through WS-V (water supply).
The surface water quality numeric standard specifically associated with recreation is fecal
coliform. For water supplies, there are 29 numeric standards based on consumption of water and
fish. Narrative standards for Class B and Class WS waters include aesthetics such as no odors
and no untreated wastes. There are other numeric standards that also apply to lakes for the
protection of aquatic life and human health. These standards also apply to all other waters of the
state and are listed under the Class C rules.

When possible, lake use support assessments are made using standards based methodologies
similar to those used for free-flowing waters. Parameters with sufficient (ten or more
observations), quality-assured observations are compared to surface water quality standards.
When standards are exceeded in more than 10 percent of the assessment period, portions or all of
the waterbody are rated Impaired. However, in many cases, the standards based approach is
incapable of characterizing the overall health of a reservoir.

For nutrient enrichment, one of the main causes of impacts to lakes and reservoirs, a more
holistic or weight of evidence approach is necessary since nutrient impacts are not always
reflected by the parameters sampled. For instance, some lakes have taste and odor problems
associated with particular algal species, yet these lakes do not have chlorophyll a concentrations
above 40 µg/l frequently enough to impair them based on the standard. In addition, each
reservoir possesses unique traits (watershed area, volume, depth, retention time, etc.) that
dramatically influence its water quality, but that cannot be evaluated through standards
comparisons. In such waterbodies, aquatic life may be Impaired even though a particular
indicator is below the standard. Where exceedances of surface water quality standards are not
sufficient to evaluate a lake or reservoir, the weight of evidence approach can take into
consideration indicators and parameters not in the standards to allow a more sound and robust
determination of water quality.

A-III-15

The weight of evidence approach uses the following sources of information to determine the
eutrophication (nutrient enrichment) level as a means of assessing lake use support in the aquatic
life category:

• Quantitative water quality parameters - dissolved oxygen, chlorophyll a, pH, etc.
• Algal bloom reports
• Fish kill reports
• Hydrologic and hydraulic characteristics – watershed size, lake volume, retention time,
volume loss, etc.
• Third party reports – citizens, water treatment plant operators, state agencies, etc.
¾ Taste and odor
¾ Sheens
¾ Odd colors
¾ Other aesthetic and safety considerations

One of the major problems associated with lakes and reservoirs is increasing eutrophication
related to nutrient inputs. Several water quality parameters help to describe the level of
eutrophication. In implementing the weight of evidence approach for eutrophication, more
consideration is given to parameters that have water quality standards. Each parameter is
assessed for percent exceedance of the state standard. The eutrophication-related parameters and
water quality indicators without numeric standards are reviewed based on interpretation of the
narrative standards in 15A NCAC 2B .0211(2) and (3). The following table lists the information
considered during a lake/reservoir use assessment, as well as the criteria used to evaluate that
information.

A modification to lake use assessment is the evaluation and subsequent rating of a lake or
reservoir by segments. In some portions of a waterbody, such as shallow coves, there may be
documented water quality problems while other areas of that waterbody do not demonstrate
significant problems. In such cases, the portion with documented problems (sufficient data,
ambient data above standards, and supporting public data) will be rated as Impaired while the
other portions are rated as Supporting or Not Rated. The following table highlights the weight of
evidence approach for assessing lake water quality.

A-III-16

Lake/Reservoir Weight of Evidence Use Assessment for Aquatic Life Category
Assessment Type Criteria
EUTROPHICATION
Water Quality Standards
Chl a >10% above standard (N>9) = P; exceeding 40 µg/l but not 10% of time = C
DO Below or above standard >10% of samples (N>9)
pH Below or above standard >10% of samples (N>9)
Turbidity >10% above standard (N>9)
% Total Dissolved Gases >10% above standard (N>9)
Temperature Minor and infrequent excursions of temperature standards due to anthropogenic
activity. No impairment of species evident (N>9).
Metals (excluding copper,
iron and zinc) >10% above standard (N>9)
Other Data
% Saturation DO >10% above >120%
Algae Blooms during 2 or more sampling events in 1 year with historic blooms.
Fish Kills related to eutrophication.
Chemically/
Biologically Treated For algal or macrophyte control - either chemicals or biologically by fish, etc.
Aesthetics Complaints Documented sheens, discoloration, etc. - written complaint and follow-up by a state
agency.
TSI Increase of 2 trophic levels from one 5-year period to next.
Historic DWQ Data Conclusions from other reports and previous use support assessments.
AGPT Algal Growth Potential Test 5-9 mg/l = C
10 or more mg/l = P
Macrophytes Limiting access to public ramps, docks, swimming areas; reducing access by fish and
other aquatic life to habitat; clogging intakes.
Taste and Odor Public complaints = P; Potential based on algal spp = C
Sediments Clogging intakes - dredging program necessary.
Note: C = of notable Concern or productive P = Problematic or highly productive
E = parameter is Exceeded, but in less than 10 percent of the measurements

A-III-17

A-III-18
References

Fels, J. 1997. North Carolina Watersheds Map. North Carolina State University Cooperative
Extension Service. Raleigh, NC.
North Carolina Department of Environment and Natural Resources (NCDENR). 2000a. Fish
Community Metric Re-Calibration and Biocriteria Development for the Inner Piedmont,
Foothills, and Eastern Mountains (Broad, Catawba, Savannah, and Yadkin River
Basins). September 22, 2000. Biological Assessment Unit. Environmental Sciences
Branch. Water Quality Section. Division of Water Quality. Raleigh, NC.
____. 2000b. Fish Community Metric Re-Calibration and Biocriteria Development for the
Outer Piedmont (Cape Fear, Neuse, Roanoke and Tar River Basins). October 17, 2000.
Ibid.
____. 2001a. Standard Operating Procedure. Biological Monitoring. Stream Fish
Community Assessment and Fish Tissue. Biological Assessment Unit. Environmental
Sciences Branch. Water Quality Section. Division of Water Quality. Raleigh, NC.
____. 2001b. Fish Community Metric Re-Calibration and Biocriteria Development for the
Western and Northern Mountains (French Broad, Hiwassee, Little Tennessee, New and
Watauga River Basins). January 05, 2001. Ibid.
USEPA. 2000. Stressor Identification Guidance Document. EPA/822/B-00/025. Office of
Water. Washington, DC.
Catawba River Basin Use Support Aquatic Life September 2004
Name
Assessment
Unit Number Description Class Subbasin Length / Area Rating Basis
Problem
Parameters
Potential
Sources
Abernethy Creek 11-135-4b From First Creek to Crowders Creek C 03-08-37 1.8 mi.I M Cause Unknown Urban Runoff/Storm Sewers
Abernethy Creek 11-135-4a From source to First Creek C 03-08-37 3.2 mi.SM
Abingdon Creek 11-39-6 From source to Lower Creek C 03-08-31 5.6 mi.SM
Armstrong Creek 11-24-14-(1)From source to Hickory Botton Creek C Tr HQW 03-08-30 10.8 mi.SM
Beaverdam Creek 11-129-9-(0.7)
From a point 0.3 mile upstream of
Gaston County SR 1626 to South Fork
Catawba River WS-IV 03-08-35 8.3 mi.SM
Blackwood Creek 11-135-7 From source to Crowders Creek C 03-08-37 4.4 mi.NR M
Blair Fork 11-39-3-1 From source to Spainhour Creek C 03-08-31 2.6 mi.NR M
Bristol Creek 11-39-8 From source to Lower Creek WS-IV 03-08-31 5.6 mi.NR M
Buck Creek (Lake Tahoma)11-19-(1)From source to Dam at Lake Tahoma WS-II & B Tr 03-08-30 166.4 ac.SM
Canoe Creek 11-33-(2)
From Burke County SR 1248 to Catawba
River WS-IV 03-08-30 5.6 mi.SM
Carpenter Creek
(Horseshoe Lake)11-129-5-9 From source to Clark Creek C 03-08-35 3.6 mi.NR M
Catawba Creek 11-130c From SR 2439 to Lake Wylie C 03-08-37 4.9 mi.I M Cause Unknown Urban Runoff/Storm Sewers
CATAWBA RIVER 11-(1)
From source to Old Fort Finishing Plant
Water Supply Intake C Tr 03-08-30 7.6 mi.SM
CATAWBA RIVER
(including backwaters of
Lake James below
elevation 1200)11-(8)
From Dam at Old Fort Finishing Plant
Water Supply Intake to North Fork
Catawba River C 03-08-30 23.5 mi.SM
CATAWBA RIVER
(including backwaters of
Rhodhiss Lake below
elevation 995)11-(31.5)
From a point 0.6 mile upstream of
Muddy Creek to a point 1.2 mile
upstream of Canoe Creek WS-IV 03-08-30 9.8 mi.SM
CATAWBA RIVER
(including backwaters of
Rhodhiss Lake below
elevation 995)11-(32.7)
From a point 0.7 mile upstream of Canoe
Creek to a point 0.6 mile upstream of
Warrior Fork WS-IV 03-08-31 3.9 mi.SM
CATAWBA RIVER
(Lake Hickory below
elevation 935)11-(51)
From Rhodhiss Dam to US Highway 321
Bridge WS-IV & B CA 03-08-32 263.1 ac.NR M
CATAWBA RIVER
(Lake Hickory below
elevation 935)11-(53)
From US Highway 321 Bridge to NC
Highway 127 WS-IV & B CA 03-08-32 1232.8 ac.NR M
CATAWBA RIVER
(Lake Hickory below
elevation 935)11-(59.5)From NC Highway 127 to Oxford Dam WS-V & B 03-08-32 2093.6 ac.NR M
CATAWBA RIVER
(Lake James below
elevation 1200)11-(23)
From North Fork Catawba River to
Bridgewater Dam WS-V & B 03-08-30 2040.9 ac.SM
A-III-19
Catawba River Basin Use Support Aquatic Life September 2004
Name
Assessment
Unit Number Description Class Subbasin Length / Area Rating Basis
Problem
Parameters
Potential
Sources
CATAWBA RIVER
(Lake James below
elevation 1200)11-(27.5)
From North Fork Catawba River to
Bridgewater Dam WS-V & B 03-08-30 3769.5 ac.SM
CATAWBA RIVER
(Lake Norman below
elevation 760)11-(74)From Lookout Shoals Dam to Lyle Creek WS-IV CA 03-08-32 265.3 ac.SM
CATAWBA RIVER
(Lake Norman below
elevation 760)11-(75)From Lyle Creek to Cowan’s Ford Dam WS-IV & B CA 03-08-32 31331.6 ac.SM
CATAWBA RIVER
(Lake Wylie below
elevation 570)11-(117)
From Mountain Island Dam to Interstate
Highway 85 Bridge at Belmont WS-IV CA 03-08-33 375.3 ac.NR M Organic Enrichment Source Unknown
CATAWBA RIVER
(Lake Wylie below
elevation 570)11-(122)
From I-85 bridge to the upstream side of
Paw Creek Arm of Lake Wylie, Catawba
River WS-IV & B CA 03-08-34 601.1 ac.I M Organic Enrichment Source Unknown
CATAWBA RIVER
(Lake Wylie below
elevation 570) North
Carolina portion 11-(123.5)
From the upstream side of Paw Creek
Arm of Lake Wylie to North Carolina-
South Carolina State Line WS-V & B 03-08-34 3418.5 ac.I M Organic Enrichment Source Unknown
CATAWBA RIVER
(Lookout Shoals Lake
below elevation 845)11-(67)
From Oxford Dam to a point 0.6 mile
upstream of mouth of Lower Little River WS-IV 03-08-32 182.7 ac.SM
CATAWBA RIVER
(Lookout Shoals Lake
below elevation 845)11-(68.5)
From a point 0.6 mile upstream of mouth
of Lower Little River to Elk Shoal Creek
(East Side)WS-IV CA 03-08-32 95.4 ac.SM
CATAWBA RIVER
(Lookout Shoals Lake
below elevation 845)11-(72)
From Elk Shoal Creek (East Side) to a
point 0.5 mile upstream of Lookout
Shoals Dam WS-IV & B CA 03-08-32 577.8 ac.SM
CATAWBA RIVER
(Lookout Shoals Lake
below elevation 845)11-(73.5)
From a point 0.5 mile upstream of
Lookout Shoals Dam to Lookout Shoals
Dam WS-IV & B CA 03-08-32 175.4 ac.SM
CATAWBA RIVER
(Mountain Island Lake
below elevation 648)11-(112)
From Cowan’s Ford Dam to Water Intake
at River Bend Steam Station WS-IV CA 03-08-33 389.4 ac.SM
CATAWBA RIVER
(Mountain Island Lake
below elevation 648)11-(114)
From Water Intake at River Bend Steam
Station to Mountain Island Dam
(Town of Mount Holly water supply
intake)WS-IV & B CA 03-08-33 1937.1 ac.SM
CATAWBA RIVER
(Rhodhiss Lake below
elevation 995)11-(37)From Johns River to Rhodhiss Dam WS-IV & B CA 03-08-31 1848.5 ac.I M Organic Enrichment Source Unknown
A-III-20
Catawba River Basin Use Support Aquatic Life September 2004
Name
Assessment
Unit Number Description Class Subbasin Length / Area Rating Basis
Problem
Parameters
Potential
Sources
Celia Creek 11-39-7-1-(2)
From a point 0.5 mile upstream of
Caldwell County SR 1325 to Husband
Creek WS-IV 03-08-31 1.3 mi.NR M
Clark Creek 11-129-5-(9.5)
From a point 0.9 mile upstream of
Walker Creek to South Fork Catawba
River WS-IV 03-08-35 1.8 mi.I M Copper Industrial Point Sources
Clark Creek (Shooks Lake)11-129-5-(0.3)b Source to Sweetwater Rd C 03-08-35 14.3 mi.I M Unknown toxicity Industrial Point Sources
Clark Creek (Shooks Lake)11-129-5-(0.3)a From source to Miller Branch C 03-08-35 3.3 mi.NR M
Cline Creek 11-129-5-2 From source to Clark Creek C 03-08-35 3.1 mi.SM
Crooked Creek 11-12 From source to Catawba River C 03-08-30 16.0 mi.SM
Crowders Creek 11-135b
From State Route 1118 to State Route
1122 C 03-08-37 3.1 mi.SM
Crowders Creek 11-135a From source to SR 1118 C 03-08-37 1.9 mi.NR M
Crowders Creek 11-135g
From State Route 2424 to North Carolina-
South Carolina State Line C 03-08-37 1.5 mi.I M Fecal Coliform Urban Runoff/Storm Sewers
Crowders Creek 11-135c
From State Route 1122 to State Route
1131 C 03-08-37 3.3 mi.I M Cause Unknown Urban Runoff/Storm Sewers
Crowders Creek 11-135d
From State Route 1131 to State Route
1108 C 03-08-37 7.3 mi.I M Cause Unknown Urban Runoff/Storm Sewers
Curtis Creek 11-10 From source to Catawba River C Tr 03-08-30 9.7 mi.SM
Duck Creek 11-62-2-(4)
From NC Highway 90 to Middle Little
River C 03-08-32 4.4 mi.SM
Dutchmans Creek 11-119-(0.5)
From source to a point 0.8 mile
downstream of Taylors Creek WS-IV 03-08-33 7.4 mi.SM
Elk Shoal Creek
(East Side)11-73-(0.5)
From source to a point 1.4 miles
upstream of mouth WS-IV 03-08-32 7.8 mi.SM
Gragg Prong 11-38-10 From source to Johns River C Tr 03-08-31 4.0 mi.SM
Greasy Creek 11-39-4 From source to Lower Creek C 03-08-31 4.6 mi.NR M
Gunpowder Creek
(Old Mill Pond)11-55-(1.5)
From a point 0.5 mile downstream of
Caldwell County SR 1127 to a point 0.8
mile downstream of Billy Branch WS-IV 03-08-32 13.4 mi.SM
Harper Creek 11-38-34-14 From source to Wilson Creek C Tr ORW 03-08-31 9.1 mi.SM
Henry Fork 11-129-1-(2)
From Morganton Water Intake to Laurel
Creek C ORW 03-08-35 19.5 mi.SM
Henry Fork 11-129-1-(12.5)a From Laurel Creek to State Route 1124 C 03-08-35 10.3 mi.IM
Henry Fork 11-129-1-(12.5)c From State Route 1143 to Jacob Fork C 03-08-35 8.6 mi.SM
Henry Fork 11-129-1-(12.5)b
From State Route 1124 to State Route
1143 C 03-08-35 4.8 mi.SM
Horseford Creek 11-54-(0.5)
From Frye Creek to a point 0.7 mile
upstream of mouth WS-IV 03-08-32 0.4 mi.I M Unknown toxicity Urban Runoff/Storm Sewers
Howards Creek 11-129-4
From source to South Fork Catawba
River C 03-08-35 13.8 mi.SM
A-III-21
Catawba River Basin Use Support Aquatic Life September 2004
Name
Assessment
Unit Number Description Class Subbasin Length / Area Rating Basis
Problem
Parameters
Potential
Sources
Hoyle Creek 11-129-15-(6)
From a point 0.2 mile downstream of
Mauney Creek to South Fork Catawba
River WS-IV CA 03-08-35 0.5 mi.SM
Hunting Creek 11-36-(0.7)
From a point 1.0 mile upstream of Burke
County SR 1940 to a point 0.4 mile
downstream of Pee Dee Branch WS-IV 03-08-31 7.4 mi.I M Cause Unknown Urban Runoff/Storm Sewers
Husband Creek 11-39-7-(1)
From source to a point 0.5 mile upstream
of Celia Creek C 03-08-31 6.0 mi.SM
Indian Creek 11-129-8-(6.5)
From a point 0.3 mile upstream of
Lincoln County SR 1169 to South Fork
Catawba River WS-IV 03-08-35 6.0 mi.I M Cause Unknown
Irish Creek 11-35-3-(2)b From Roses Creek to Warrior Fork WS-III 03-08-31 3.0 mi.I M Habitat degradation Crop-related Sources
Irwin Creek 11-137-1 From source to Sugar Creek C 03-08-34 11.8 mi.I M Fecal Coliform Urban Runoff/Storm Sewers
Jacktown Creek 11-32-1-4-1 From source to Youngs Fork C 03-08-30 2.4 mi.I M Cause Unknown Land Development
Jacob Fork 11-129-2-(4)From Little River to Camp Creek WS-III ORW 03-08-35 6.8 mi.SM
Johns River 11-38-(35.5)
From a point 0.5 mile upstream of Sims
Branch to a point 0.7 mile downstream of
NC Highway 18 WS-IV HQW 03-08-31 6.9 mi.SM
Killian Creek 11-119-2-(0.5)b
From Anderson Creek to a point 1.2
miles upstream of mouth C 03-08-33 3.2 mi.I M Cause Unknown Land Development
Killian Creek 11-119-2-(0.5)a From source to Anderson Creek C 03-08-33 11.6 mi.SM
Limekiln Creek 11-129-16-2 From source to Long Creek WS-II 03-08-36 1.9 mi.SM
Linville River 11-29-(4.5)
From Grandmother Creek to Linville
Falls B Tr 03-08-30 15.3 mi.SM
Linville River 11-29-(19)
From southern Boundary of Daniel
Boone Wildlife Management Area to
Lake James, Catawba River B HQW 03-08-30 7.1 mi.SM
Little Buck Creek 11-19-11
From source to Lake Tahoma, Buck
Creek WS-II & B Tr 03-08-30 4.4 mi.SM
Little Sugar Creek 11-137-8b From Arcdale Road to NC 51 C 03-08-34 5.5 mi.I M Fecal Coliform Urban Runoff/Storm Sewers
Long Creek 11-120-(2.5)
From a point 0.6 mile downstream of
Mecklenburg County SR 2074 to a point
0.4 mile upstream of Mecklenburg
County SR 1606 WS-IV 03-08-34 11.3 mi.I M Habitat degradation Breached Mill Dam
Long Creek 11-129-16-(4)
From Mountain Creek to South Fork
Catawba River C 03-08-36 15.3 mi.SM
Lower Creek 11-39-(0.5)a From source to Zack’s Fork C 03-08-31 8.8 mi.I M Habitat degradation Urban Runoff/Storm Sewers
Lower Creek 11-39-(0.5)b
From Zack’s Fork to Caldwell County SR
1143 C 03-08-31 5.1 mi.I M Habitat degradation Urban Runoff/Storm Sewers
Lower Creek 11-39-(6.5)
From Caldwell County SR 1143 to a
point 0.7 mile downstream of Bristol
Creek WS-IV 03-08-31 6.8 mi.I M Habitat degradation Urban Runoff/Storm Sewers
A-III-22
Catawba River Basin Use Support Aquatic Life September 2004
Name
Assessment
Unit Number Description Class Subbasin Length / Area Rating Basis
Problem
Parameters
Potential
Sources
Lower Little River 11-69-(0.5)
From source to a point 0.5 mile upstream
of mouth of Stirewalt Creek C 03-08-32 14.0 mi.I M Habitat degradation Source Unknown
Lower Little River 11-69-(5.5)
From a point 0.5 mile upstream of of
mouth Stirewalt Creek to a point 0.8 mile
upstream of mouth WS-IV 03-08-32 8.6 mi.SM
Lyle Creek 11-76-(3.5)
From Bakers Creek to US Highways 64
and 70 WS-IV 03-08-32 6.3 mi.SM
Mackey Creek 11-15-(3.5)a From Laurel Fork Creek to US 70 C 03-08-30 1.8 mi.SM
Mackey Creek 11-15-(3.5)b From US 70 to Catawba River C 03-08-30 0.8 mi.SM
Maiden Creek 11-129-5-7-2-(1)
From source to a point 0.7 mile upstream
from backwaters of Maiden Reservoir WS-II 03-08-35 4.9 mi.I M Cause Unknown
McAlpine Creek
(Waverly Lake)11-137-9c From NC 51 to NC 521 C 03-08-34 4.6 mi.I M turbidity Urban Runoff/Storm Sewers
McDowell Creek 11-115-(1.5)b
From SR 2136 Mecklengurg Co to a
point 0.7 mile upstream of mouth WS-IV 03-08-33 2.9 mi.I M Cause Unknown Land Development
McDowell Creek 11-115-(1.5)a
From US Highway 21 to SR 2136
Mecklenburg Co WS-IV 03-08-33 4.4 mi.I M Cause Unknown Land Development
McGalliard Creek 11-44-(3)
From a point 0.6 mile upstream of mouth
to Rhodhiss Lake, Catawba River WS-IV CA 03-08-31 3.9 mi.I M Cause Unknown Urban Runoff/Storm Sewers
McLin Creek 11-76-5-(3)
From a point 0.2 mile upstream of
Catawba County SR 1722 to Lyle Creek WS-IV CA 03-08-32 0.7 mi.SM
Middle Little River 11-62 From source to Duck Creek C 03-08-32 21.5 mi.SM
Mill Creek 11-7-(0.5)From source to Swannanoa Creek C Tr HQW 03-08-30 5.0 mi.SM
Muddy Fork 11-69-4 From source to SR 1409 C 03-08-32 6.8 mi.SM
Mulberry Creek 11-38-32-(15)
From Dam at Mulberry Beach to Johns
River C 03-08-31 5.4 mi.SM
North Fork Catawba River 11-24-(2.5)a
From mouth of Laurel Branch to
Stillhouse Branch B Tr 03-08-30 7.1 mi.SM
North Fork Catawba River 11-24-(2.5)b
From Stillhouse Branch to Armstrong
Creek B Tr 03-08-30 3.5 mi.IM
North Fork Catawba River 11-24-(13)
From Armstrong Creek to Lake James,
Catawba River C 03-08-30 7.0 mi.NR M
North Muddy Creek 11-32-1 From source to Muddy Creek C 03-08-30 18.4 mi.SM
Paddy Creek 11-28
From source to 1.5 mi upstream of Lake
James C Tr 03-08-30 4.6 mi.SM
Pinch Gut Creek 11-129-5-7 From source to Clark Creek C 03-08-35 7.2 mi.SM
A-III-23
Catawba River Basin Use Support Aquatic Life September 2004
Name
Assessment
Unit Number Description Class Subbasin Length / Area Rating Basis
Problem
Parameters
Potential
Sources
Pott Creek 11-129-3-(0.7)
From a point 0.3 mile upstream of
Lincoln County SR 1217 to South
Catawba Fork River WS-IV 03-08-35 3.2 mi.SM
Silver Creek 11-34-(0.5)
From source to a point 1.3 miles
downstream of Clear Creek C 03-08-31 15.4 mi.SM
Silver Creek 11-56-(2)
From a point 0.7 mile upstream of mouth
to Lake Hickory, Catawba River WS-IV CA 03-08-32 0.8 mi.SM
Sixmile Creek 11-138-3
From source to North Carolina-South
Carolina State Line C 03-08-38 8.8 mi.I M Cause Unknown Urban Runoff/Storm Sewers
Smoky Creek 11-41-(1)
From source to a point 0.6 mile upstream
of mouth WS-IV 03-08-31 7.5 mi.SM
South Fork Catawba River 11-129-(0.5)
From source to Catawba-Lincoln County
Line WS-V 03-08-35 8.4 mi.SM
South Fork Catawba River 11-129-(15.5)
From a point 0.4 mile upstream of Long
Creek to Cramerton Dam and Lake
Wylie at Upper Armstrong Bridge WS-V 03-08-36 18.1 mi.SM
South Fork Crowders Creek 11-135-10 North Carolina Portion C 03-08-37 5.7 mi.NR M
South Muddy Creek 11-32-2 From source to Muddy Creek C 03-08-30 16.1 mi.SM
Spainhour Creek 11-39-3 From source to Lower Creek C 03-08-31 4.7 mi.I M Cause Unknown Urban Runoff/Storm Sewers
Sugar Creek 11-137a
From source to below WWTP, SR 1156,
Mecklenburg C 03-08-34 0.3 mi.I M Cause Unknown Urban Runoff/Storm Sewers
Sugar Creek 11-137b
From SR 1156 Mecklenburg to Highway
51 C 03-08-34 10.9 mi.NR M Cause Unknown Urban Runoff/Storm Sewers
Swannanoa Creek 11-7-9 From source to Mill Creek C Tr 03-08-30 3.2 mi.SM
Toms Creek 11-21-(2)
From Harris Creek to McDowell County
SR 1434 C HQW 03-08-30 6.6 mi.SM
Town Creek 11-129-5-4 From source to Clark Creek C 03-08-35 3.8 mi.SM
Twelvemile Creek 11-138
From source to North Carolina-South
Carolina State Line C 03-08-38 3.0 mi.SM
Upper Creek 11-35-2-(13)
From Dam at Clear Water Beach Lake to
Warrior Fork WS-III Tr HQW 03-08-31 4.3 mi.SM
Upper Little River
(Cedar Creek)11-58-(5.5)
From Morris Creek to a point 0.5 mile
upstream of mouth WS-IV 03-08-32 9.8 mi.SM
Warrior Fork 11-35-(1)
From source to a point 0.6 mile upstream
of City of Morganton water supply intake WS-III 03-08-31 4.9 mi.SM
White Mill Creek 11-39-8-1-(2)
From a point 0.6 mile downstream of
Burke County-Caldwell County Line to
Bristol Creek WS-IV 03-08-31 3.4 mi.NR M
A-III-24
Catawba River Basin Use Support Aquatic Life September 2004
Name
Assessment
Unit Number Description Class Subbasin Length / Area Rating Basis
Problem
Parameters
Potential
Sources
Wilson Creek 11-38-34 From source to Johns River B Tr ORW 03-08-31 23.3 mi.SM
Youngs Fork
(Corpening Creek)11-32-1-4a From source to Marion WWTP C 03-08-30 3.6 mi.I M Cause Unknown Major Municipal Point Source
Youngs Fork
(Corpening Creek)11-32-1-4b
From Marion WWTP to North Muddy
Creek C 03-08-30 1.9 mi.I M Cause Unknown Urban Runoff/Storm Sewers
Zacks Fork Creek 11-39-1 From source to Lower Creek C 03-08-31 8.0 mi.SM
NOTES
"Rating" = Use Support Rating
"Basis" = Rating Basis
"Habitat degradation" is identified where there is a notable reduction in habitat diversity or change in habitat quality. This term includes sedimentation,
bank erosion, channelization, lack of riparian vegetation, loss of pools or riffles, loss of woody habitat, and stream bed scour.
ABBREVIATION KEY
p = Point Source Pollution (Major source)
np = Nonpoint Source Pollution
M = Monitored
S = Supporting
I = Impaired
NR = Not Rated
A-III-25
Catawba River Basin Use Support Recreation September 2004
Name
Assessment
Unit Number Description Class Subbasin Length / Area Rating Basis
CATAWBA RIVER
(including backwaters of Lake James
below elevation 1200) 11-(8)
From Dam at Old Fort Finishing Plant Water
Supply Intake to North Fork Catawba River C 03-08-30 23.5 mi. S M
North Fork Catawba River 11-24-(13)
From Armstrong Creek to Lake James,
Catawba River C 03-08-30 7.0 mi. S M
Linville River 11-29-(19)
From southern Boundary of Daniel Boone
Wildlife Management Area to Lake James,
Catawba River B HQW 03-08-30 7.1 mi. S M
CATAWBA RIVER
(including backwaters of Rhodhiss
Lake below elevation 995) 11-(31)
From Bridgewater Dam (Linville Dam) to a
point 0.6 mile upstream of Muddy Creek WS-V 03-08-30 1.1 mi. S M
CATAWBA RIVER
(including backwaters of Rhodhiss
Lake below elevation 995) 11-(31.5)
From a point 0.6 mile upstream of Muddy
Creek to a point 1.2 mile upstream of Canoe
Creek WS-IV 03-08-30 9.8 mi. S M
Wilson Creek 11-38-34 From source to Johns River B Tr ORW 03-08-31 23.3 mi. S M
Lower Creek 11-39-(6.5)
From Caldwell County SR 1143 to a point 0.7
mile downstream of Bristol Creek WS-IV 03-08-31 6.8 mi. NR M
CATAWBA RIVER
(Lake Hickory below elevation 935) 11-(53)
From US Highway 321 Bridge to NC
Highway 127 WS-IV&B CA 03-08-32 1232.8 ac. S M
CATAWBA RIVER
(Lake Hickory below elevation 935) 11-(59.5) From NC Highway 127 to Oxford Dam WS-V&B 03-08-32 2093.6 ac. S M
Lower Little River 11-69-(0.5)
From source to a point 0.5 mile upstream of
mouth of Stirewalt Creek C 03-08-32 14.0 mi. NR M
CATAWBA RIVER
(Lake Norman below elevation 760) 11-(74) From Lookout Shoals Dam to Lyle Creek WS-IV CA 03-08-32 265.3 ac. S M
CATAWBA RIVER
(Lake Norman below elevation 760) 11-(75) From Lyle Creek to Cowan’s Ford Dam WS-IV&B CA 03-08-32 31331.6 ac. S M
CATAWBA RIVER
(Mountain Island Lake below
elevation 648) 11-(114)
From Water Intake at River Bend Steam
Station to Mountain Island Dam (Town of
Mount Holly water supply intake) WS-IV&B CA 03-08-33 1937.1 ac. S M
CATAWBA RIVER
(Lake Wylie below elevation 570) 11-(117)
From Mountain Island Dam to Interstate
Highway 85 Bridge at Belmont WS-IV CA 03-08-33 375.3 ac. S M
Dutchmans Creek 11-119-(0.5)
From source to a point 0.8 mile downstream
of Taylors Creek WS-IV 03-08-33 7.4 mi. S M
A-III-26
Catawba River Basin Use Support Recreation September 2004
Name
Assessment
Unit Number Description Class Subbasin Length / Area Rating Basis
Long Creek 11-120-(2.5)
From a point 0.6 mile downstream of
Mecklenburg County SR 2074 to a point 0.4
mile upstream of Mecklenburg County SR
1606 WS-IV 03-08-34 11.3 mi. NR M
CATAWBA RIVER
(Lake Wylie below elevation 570) 11-(122)
From I-85 bridge to the upstream side of Paw
Creek Arm of Lake Wylie, Catawba River WS-IV&B CA 03-08-34 601.1 ac. S M
CATAWBA RIVER
(Lake Wylie below elevation 570)
North Carolina portion 11-(123.5)
From the upstream side of Paw Creek Arm of
Lake Wylie to North Carolina-South Carolina
State Line WS-V&B 03-08-34 3418.5 ac. S M
South Fork Catawba River 11-129-(0.5) From source to Catawba-Lincoln County Line WS-V 03-08-35 8.4 mi. S M
Henry Fork 11-129-1-(12.5)c From State Route 1143 to Jacob Fork C 03-08-35 8.6 mi. S M
Henry Fork 11-129-1-(12.5)b From State Route 1124 to State Route 1143 C 03-08-35 4.8 mi. S M
Clark Creek 11-129-5-(9.5)
From a point 0.9 mile upstream of Walker
Creek to South Fork Catawba River WS-IV 03-08-35 1.8 mi. NR M
Indian Creek 11-129-8-(5)
From a point 0.4 mile upstream of mouth of
Lick Fork to a point 0.3 mile upstream of
Lincoln County SR 1169 C 03-08-35 2.6 mi. S M
South Fork Catawba River 11-129-(15.5)
From a point 0.4 mile upstream of Long
Creek to Cramerton Dam and Lake Wylie at
Upper Armstrong Bridge WS-V 03-08-36 18.1 mi. S M
Long Creek 11-129-16-(4)
From Mountain Creek to South Fork Catawba
River C 03-08-36 15.3 mi. NR M
Crowders Creek 11-135e From State Route 1108 To NC 321 C 03-08-37 1.5 mi. I M
Crowders Creek 11-135b From State Route 1118 to State Route 1122 C 03-08-37 3.1 mi. I M
Crowders Creek 11-135a From source to SR 1118 C 03-08-37 1.9 mi. I M
Crowders Creek 11-135g
From State Route 2424 to North Carolina-
South Carolina State Line C 03-08-37 1.5 mi. I M
Crowders Creek 11-135f From State Route 321 to State Route 2424 C 03-08-37 1.4 mi. I M
Crowders Creek 11-135c From State Route 1122 to State Route 1131 C 03-08-37 3.3 mi. I M
Crowders Creek 11-135d From State Route 1131 to State Route 1108 C 03-08-37 7.3 mi. I M
Blackwood Creek 11-135-7 From source to Crowders Creek C 03-08-37 4.4 mi. I M
Sugar Creek 11-137a
From source to below WWTP, SR 1156,
Mecklenburg C 03-08-34 0.3 mi. NR M
A-III-27
Catawba River Basin Use Support Recreation September 2004
Name
Assessment
Unit Number Description Class Subbasin Length / Area Rating Basis
Sugar Creek 11-137b From SR 1156 Mecklenburg to Highway 51 C 03-08-34 10.9 mi. NR M
Irwin Creek 11-137-1 From source to Sugar Creek C 03-08-34 11.8 mi. NR M
Little Sugar Creek 11-137-8b From source to Arcdale Road C 03-08-34 5.5 mi. NR M
McAlpine Creek (Waverly Lake) 11-137-9a From source to SR 3356, (Sardis Road) C 03-08-34 8.5 mi. NR M
Twelvemile Creek 11-138
From source to North Carolina-South
Carolina State Line C 03-08-38 3.0 mi. NR M
NOTES
"Rating" = Use Support Rating
"Basis" = Rating Basis
"Habitat degradation" is identified where there is a notable reduction in habitat diversity or change in habitat quality. This term includes sedimentation,
bank erosion, channelization, lack of riparian vegetation, loss of pools or riffles, loss of woody habitat, and stream bed scour.
ABBREVIATION KEY
p = Point Source Pollution (Major source)
np = Nonpoint Source Pollution
M = Monitored
S = Supporting
I = Impaired
NR = Not Rated
A-III-28