HomeMy WebLinkAboutChapter 8 Use SupportNC
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8.1
CHAPTER 8
2010 Use sUpport &
Methodology
IN thE NEW RIVER BASIN
2010 IR
CAtEgoRy
INtEgRAtED REPoRtINg CAtEgoRIES foR INDIVIDUAL ASSESSMENt UNIt/USE SUPPoRt CAtEgoRy/
PARAMEtER ASSESSMENtS. A SINgLE AU CAN hAVE MULtIPLE ASSESSMENtS DEPENDINg oN DAtA
AVAILABLE AND CLASSIfIED USES.
1 All designated uses are monitored and supporting
1b Designated use was impaired, other management strategy in place and no standards violations for the parameter of interest (POI)
1nc DWQ have made field determination that parameter in exceedance is due to natural conditions
1r Assessed as supporting watershed is in restoration effort status
1t No criteria exceeded but approved TMDL for parameter of interest
2 Some designated uses are monitored and supporting none are impaired Overall only
2b Designated use was impaired other management strategy in place and no standards violations Overall
only
2r Assessed as supporting watershed is in restoration effort status overall only
2t No criteria exceeded but approved TMDL for POI Overall only
3a Instream/monitoring data are inconclusive (DI)
3b No Data available for assessment
3c No data or information to make assessment
3n1 Chlorophyll a exceeds TL value and SAC is met-draft
3n2 Chlorophyll a exceeds EL value and SAC is not met first priority for further monitoring-draft
3n3 Chlorophyll a exceeds threshold value and SAC is not met first second priority for further monitoring-draft
3n4 Chlorophyll a not available determine need to collect-draft
3t No Data available for assessment –AU is in a watershed with an approved TMDL
4b Designated use impaired other management strategy expected to address impairment
4c Designated use impaired by something other than pollutant
4cr Recreation use impaired no instream monitoring data or screening criteria exceeded
4cs Shellfish harvesting impaired no instream monitoring data-no longer used
4ct Designated use impaired but water is subject to approved TMDL or under TMDL development
4s Impaired Aquatic Life with approved TMDL for Aquatic Life POI or category 5 listing
4t Designated use impaired approved TMDL
5 Designated use impaired because of biological or ambient water quality standards violations and needing
a TMDL
5r Assessed as impaired watershed is in restoration effort status
NC
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8.2
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8.3
AU_NameAU_Number AU_Description LengthArea AU_Units Classification
All 13,123 Waters in NC are in Category 5-303(d) List for Mercury due to statewide fish consumption advice for several fish species
NC 2010 Integrated Report
North Fork New River 0505000101New River Basin Watershed
Upper New River 05050001New River Basin Subbasin
North Fork New River 0505000101New River Basin Watershed
Big Horse Creek10-2-21-(4.5)From SR#1362 to SR#1353 (Tuckerdale)5.5 FW Miles C;Tr:+
1
Big Horse Creek
(Horse Creek)
10-2-21-(7)From SR#1353 (Tuckerdale) to North Fork
New R
6.5 FW Miles C:+
1
1
Big Laurel Creek10-2-14 From source to North Fork New River 17.5 FW Miles C;Tr:+
1
1
Brush Fork10-2-8 From source to North Fork New River 5.1 FW Miles C;Tr:+
1
Buffalo Creek10-2-20 From source to North Fork New River 9.7 FW Miles C;Tr:+
1
3a
Helton Creek10-2-27 From NC-VA State Line to North Fork New
River
19.0 FW Miles C;Tr:+
1
3a
Hoskin Fork10-2-7 From source to North Fork New River 5.2 FW Miles C;Tr:+
1
Little Buffalo Creek10-2-20-1 From source to Buffalo Creek 4.4 FW Miles C;Tr:+
5
Little Horse Creek10-2-21-8 From source to Big Horse Creek 10.9 FW Miles C;Tr:+
1
Little Phoenix Creek10-2-23 From source to North Fork New River 4.6 FW Miles C;Tr:+
1
Long Shoals Creek10-2-25 From source to North Fork New River 2.7 FW Miles C;Tr:+
1
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8.4
AU_NameAU_Number AU_Description LengthArea AU_Units Classification
All 13,123 Waters in NC are in Category 5-303(d) List for Mercury due to statewide fish consumption advice for several fish species
NC 2010 Integrated Report
North Fork New River 0505000101New River Basin Watershed
Middle Fork Little
Horse Creek
10-2-21-8-1 From source to Little Horse Creek 4.5 FW Miles C;Tr:+
1
Millpond Branch10-2-28 From source to North Fork New River 2.0 FW Miles C:+
1
North Fork New River10-2-(1)From source to Three Top Creek 14.1 FW Miles C;Tr:+
1
1
North Fork New River10-2-(12)From Three Top Creek to New River 36.5 FW Miles C:+
1
1
1
Rich Hill Creek10-2-15 From source to North Fork New River 4.9 FW Miles C;Tr:+
1
Roundabout Creek10-2-10 From source to North Fork New River 4.0 FW Miles C;Tr:+
1
Three Top Creek10-2-13 From source to North Fork New River 13.2 FW Miles C;Tr:+
1
3a
South Fork New River 0505000102New River Basin Watershed
Cranberry Creek
(Mulberry Creek)
10-1-37 From source to South Fork New River 18.9 FW Miles B;Tr:+
1
1
East Fork South Fork
New River
10-1-3-(1)From source to Watauga County SR 1524 2.3 FW Miles WS-IV;Tr:+
5
East Fork South Fork
New River
10-1-3-(8)From .8 mile downstream of Watauga Co
SR 1524 to S Fk New River
0.5 FW Miles WS-IV;CA:+
1
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AU_NameAU_Number AU_Description LengthArea AU_Units Classification
All 13,123 Waters in NC are in Category 5-303(d) List for Mercury due to statewide fish consumption advice for several fish species
NC 2010 Integrated Report
South Fork New River 0505000102New River Basin Watershed
Howard Creek10-1-9-(6)From the Appalachian State University Raw
Water Supply Intake Dam to South Fork
New River
3.6 FW Miles C;Tr,HQW
1
3a
Little Peak Creek10-1-35-4 From source to Peak Creek 2.8 FW Miles B;Tr:+
4s
Meat Camp Creek10-1-10 From source to South Fork New River 10.4 FW Miles C;Tr:+
1
3a
Middle Fork South
Fork New River
10-1-2-(15)From 0.4 mile downstr of US Hwy 221 &
321 to South Fk New River
0.5 FW Miles WS-IV;CA:+
1
3a
Middle Fork South
Fork New River
10-1-2-(6)From Brown Branch to Boone Dam 3.5 FW Miles WS-IV;Tr:+
1
Naked Creek10-1-32b From 0.4 miles above Jefferson WWTP to
South Fork New River
2.5 FW Miles C:+
1
5
Norris Fork10-1-10-2 From source to Meat Camp Creek 4.3 FW Miles C;Tr:+
1
Obids Creek10-1-27-(2)From a point 0.9 mile downstream of NC
Hwy 163 to South Fork New River
2.8 FW Miles WS-IV;Tr:+
1
1
Ore Knob Branch10-1-35-3 From source to Peak Creek 0.9 FW Miles B;Tr:+
4s
Peak Creek10-1-35-(2)a From Water Supply Dam at Appalachian
Sulphides, Inc to Ore Knob Branch
2.1 FW Miles B;Tr:+
1
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8.6
AU_NameAU_Number AU_Description LengthArea AU_Units Classification
All 13,123 Waters in NC are in Category 5-303(d) List for Mercury due to statewide fish consumption advice for several fish species
NC 2010 Integrated Report
South Fork New River 0505000102New River Basin Watershed
Peak Creek10-1-35-(2)b From Ore Knob Branch to South Fork New
River
2.9 FW Miles B;Tr:+
4s
Pine Orchard Creek10-1-15-1 From source to Elk Creek 3.5 FW Miles C;Tr:+
1
Pine Swamp Creek
(Pine Swamp)
10-1-24 From source to South Fork New River 5.5 FW Miles C:+
1
Prathers Creek10-1-38 From source to South Fork New River 11.1 FW Miles B;Tr:+
1
Roan Creek10-1-31-(2)From 0.5 mile upstream of mouth to South
Fork New River
0.4 FW Miles WS-
IV;Tr,CA:+
1
1
South Beaver
Creek(Lake Ashe)
10-1-25-2a From source to Lake Ashe 5.1 FW Miles C;Tr:+
1
South Fork New River10-1-(20.5)From a point 0.4 mile upstream of Couches
Creek to a point 2.8 mile upstream of Obids
Creek
21.8 FW Miles WS-V;HQW
1
South Fork New River10-1-(26)b From Obids Creek to a point 0.6 miles
upstream of Roan Creek
6.6 FW Miles WS-IV;HQW
1
1
1
1
South Fork New River10-1-(3.5)a From Winkler Creek to 0.1 miles
downstream of Hunting Lane
0.3 FW Miles C:+
5
1
1
1
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8.7
AU_NameAU_Number AU_Description LengthArea AU_Units Classification
All 13,123 Waters in NC are in Category 5-303(d) List for Mercury due to statewide fish consumption advice for several fish species
NC 2010 Integrated Report
South Fork New River 0505000102New River Basin Watershed
South Fork New River10-1-(3.5)b From 0.1 mile downstream Hunting Lane to
US Hwy.221/421
5.1 FW Miles C:+
5
1
1
1
South Fork New River10-1-(33.5)From Dog Creek to New River 22.5 FW Miles B;ORW
1
1
1
UT MILL CR10-1-18ut4 Source to MILL CR 1.3 FW Miles
1
UT S FK NEW R10-1-(14.5)ut4 Source to S FK NEW R 1.0 FW Miles
3a
Winkler Creek10-1-4-(3.5)b From Winkler Creek Road (SR #1549) to
South Fork New River
1.7 FW Miles C;Tr:+
1
Fox Creek-New River 0505000103New River Basin Watershed
Grassy Creek10-3 From North Carolina-Virginia State 4.1 FW Miles C;Tr:+
1
1
New River (North
Carolina Portion)
10b From first point of crossing state line to last
point of crossing state line
6.4 FW Miles C;ORW
3a
1
3a
Little River-New River 0505000104New River Basin Watershed
Bledsoe Creek10-9-7 From source to Little River 5.9 FW Miles C;Tr
1
Brush Creek10-9-10 From source to Little River 27.8 FW Miles C;Tr
1
1
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8.8
AU_NameAU_Number AU_Description LengthArea AU_Units Classification
All 13,123 Waters in NC are in Category 5-303(d) List for Mercury due to statewide fish consumption advice for several fish species
NC 2010 Integrated Report
Little River-New River 0505000104New River Basin Watershed
Crab Creek10-9-12 From source to Little River 7.8 FW Miles C;Tr
1
5
Elk Creek (North
Carolina Portion)
10-6-(2)From U.S. Hwy. 221 to New River 7.4 FW Miles C:+
1
1
Glade Creek10-9-9 From source to Little River 8.3 FW Miles C;Tr
1
1
Laurel Branch (Laurel
Creek)
10-9-10-2 From source to Brush Creek 5.2 FW Miles C;Tr
1
Little River10-9-(6)From dam at Sparta Lake to NC 18 (Blevins
Crossroads)
17.5 FW Miles C
1
1
1
Little River (North
Carolina Portion)
10-9-(11.5)From NC 18 (Blevins Crossroads) to New
River (state line)
3.6 FW Miles C;HQW
1
Little River (Sparta
Lake)
10-9-(1)a From source to Sparta Lake at Pine Swamp
Creek
11.6 FW Miles C;Tr
1
1
Moccasin Creek10-9-11 From source to Little River 4.4 FW Miles C
1
Pine Swamp Creek10-9-5 From source to Little River 5.2 FW Miles C;Tr
1
1
UT CRAB CR10-9-12ut8ut4 Source to CRAB CR 0.7 FW Miles
1
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8.9
AU_NameAU_Number AU_Description LengthArea AU_Units Classification
All 13,123 Waters in NC are in Category 5-303(d) List for Mercury due to statewide fish consumption advice for several fish species
NC 2010 Integrated Report
Little River-New River 0505000104New River Basin Watershed
UT UT CRAB CR10-9-12ut8 Source to UT CRAB CR 4.5 FW Miles
1
Waterfalls Creek10-9-4 From source to Little River 4.3 FW Miles C;Tr
1
Wolf Branch10-9-9-1 From source to Glade Creek 2.8 FW Miles C;Tr
1
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8.10
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8.11
Page 1 of 14 2010 Integrated Report Methodology EPA Approved 8/31/2010
North Carolina Division of Water Quality
2010
Use Assessment Methodology
EPA Approved August 31, 2010
NC
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8.12
Page 2 of 14 2010 Integrated Report Methodology EPA Approved 8/31/2010
Table of Contents
Purpose ................................................................................................................................................... 3
Assessment Units and Water Quality Classifications ...................................................................... 3
Data Window/Assessment Period ...................................................................................................... 4
Data Availability and Quality .............................................................................................................. 4
Use Support Categories and Water Quality Standards .................................................................. 4
Aquatic Life Assessment Methodology .............................................................................................. 4
Numerical Water Quality Standards .............................................................................................. 4
Dissolved Oxygen (DO) Standards ............................................................................................ 5
Freshwater Dissolved Oxygen (DO) Assessment (Class C, B, WS) ...................................... 5
Saltwater Dissolved Oxygen (DO) Assessment (Class SC, SB, SA) ..................................... 5
Trout Water Dissolved Oxygen (DO) Assessment (Supplemental Class Tr) ....................... 5
Swamp Water Dissolved Oxygen (DO) Assessment (Supplemental Class Sw) ................. 5
pH ........................................................................................................................................................ 6
pH Standards ................................................................................................................................. 6
Low pH Assessment (Class C, SC, B, SB, SA, WS) ................................................................. 6
High pH Assessment (Class C, SC, B, SB, SA, WS) ................................................................ 6
Swamp Water Low pH Assessment (Supplemental Class Sw) .............................................. 7
Temperature Use Assessment ........................................................................................................ 7
Temperature Standards ............................................................................................................... 7
Temperature Assessment ............................................................................................................ 7
Temperature Screening Criteria for Trout Waters (Supplemental Class Tr) ...................... 8
Assessment of Extreme Temperature Conditions ................................................................... 8
Chlorophyll a ...................................................................................................................................... 8
Chlorophyll a Standard ................................................................................................................ 8
Chlorophyll a Standards Assessment ........................................................................................ 8
Toxic Substances and Action Levels Metals ................................................................................. 9
Toxic Substances Numerical Standards .................................................................................... 9
Metals Action Level Standards .................................................................................................... 9
Toxic Substances and Action Level Metals Assessment ......................................................... 9
Turbidity ........................................................................................................................................... 10
Turbidity Standards .................................................................................................................... 10
Turbidity Assessment ................................................................................................................. 10
Ecological/Biological Integrity ....................................................................................................... 11
Aquatic Life Narrative Standards.............................................................................................. 11
Aquatic Life Assessment ............................................................................................................ 11
Recreation Assessment Methodology .............................................................................................. 11
Pathogen Indicator Standards ...................................................................................................... 12
Fecal Coliform Bacteria Assessment Criteria .............................................................................. 12
Fecal Coliform Bacteria Screening Assessment ......................................................................... 12
Enterrococci Assessment Criteria ................................................................................................. 12
Enterrococcus Screening Assessment ......................................................................................... 12
Advisory Posting Assessment ....................................................................................................... 12
Shellfish Harvesting Assessment Methodology ............................................................................. 13
Shellfish Harvesting Standards .................................................................................................... 13
Fecal Coliform Bacteria Assessment Criteria .............................................................................. 13
DEH Shellfish Sanitation Growing Area Classification Assessment ........................................ 13
Water Supply Assessment Methodology ......................................................................................... 13
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8.13
Page 3 of 14
2010 Integrated Report Methodology EPA Approved 8/31/2010
Water Supply Standards ................................................................................................................ 13
Water Supply Assessment ............................................................................................................. 13
Fish Consumption Assessment Methodology ................................................................................. 14
Polychlorinated biphenyls (PCBs) Assessment Criteria ............................................................ 14
Dioxin Assessment Criteria ........................................................................................................... 14
Mercury Assessment Criteria ........................................................................................................ 14
Purpose
Section 303(d) of the federal Clean Water Act (CWA) which Congress enacted in
1972 requires States, Territories and authorized Tribes to identify and establish a
priority ranking for waterbodies for which technology-based effluent limitations
required by section 301 are not stringent enough to attain and maintain applicable
water quality standards, establish total maximum daily loads (TMDLs) for the
pollutants causing impairment in those waterbodies, and submit, from time to time,
the list of impaired waterbodies and TMDLs to the U.S. Environmental Protection
Agency (EPA). Current federal rules require states to submit 303(d) lists biennially,
by April 1st of every even numbered year. The “303(d) list” is technically
considered the impaired waters listed as Category 5, requiring a TMDL. EPA is
required to approve or disapprove the state-developed §303(d) list within 30 days.
For each water quality limited segment impaired by a pollutant and identified in the
§303(d) list, a Total Maximum Daily Load (TMDL) must be developed.
Assessment Units and Water Quality Classifications
Water quality assessments are based on water quality classifications as well as data
availability. Water quality classifications are associated with a stream reach or area
that is described in the schedule of classifications. Reaches vary in length or area
and are sometimes split into smaller units to represent application of water quality
data. Classifications are represented by a series of numbers called index numbers,
27-33-43-(1), as an example. Water quality assessments are applied to
assessment units or AUs. AUs are, for the most part, the same as index numbers.
When an AU is subdivided because of data applicability a letter is added to indicate
this smaller unit. For example, if Index number 27-33-43-(1) (12 miles in length)
is divided into three different segments because of three different available data
types the new segments would be 27-33-43-(1)a, 27-33-43-(1)b and 27-33-43-
(1)c. The combined mileage of the AUs would be 12 miles.
Decisions on the length or area to apply data to are based on the data type,
waterbody characteristics, stations indicating similar water quality, watershed
information and landmarks on which to base descriptions. The AUs where water
quality concerns are evident are used as markers. Solutions to water quality
concerns, including TMDLs, typically encompass entire watersheds.
NC
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Page 4 of 14
2010 Integrated Report Methodology EPA Approved 8/31/2010
Data Window/Assessment Period
The data window for the 2010 Water Quality Use Assessment (305(b) and 303(d)
Integrated Reporting) includes data collected in calendar years 2004 through 2008
(five years). Some AUs may have biological data collected earlier for waters that
have not been resampled during this data window or where the current impairment
is based on that sample. The data collection year is noted for each AU.
Data Availability and Quality
Data are collected by various state and federal agencies. NC Department of
Environment and Natural Resources (NCDENR) Division of Water Quality (DWQ)
collects most of the data used for water quality assessments. There are significant
data sets collected by NCDENR Division of Environmental Health (DEH) for use in
coastal water quality assessment. The United States Geological Survey (USGS) also
provides data in several AUs. Local governments and environmental groups as well
as industry, municipal and university coalitions also provide data. Submitted data
sets must include an approved Quality Assurance Project Plan (QAPP) or other
documentation to assure that the data were collected in a manner consistent with
agency data. A standing solicitation for data is maintained on the DWQ website.
DWQ evaluates all data and information submitted.
Use Support Categories and Water Quality Standards
There are numerical and narrative water quality standards that are in place to
protect the various best uses of North Carolina waters. Best uses include aquatic
life or biological integrity, recreation or swimming, fish consumption, shellfish
harvesting and water supply. Water quality assessments are based on the
standards and data availability for the applicable use support category- aquatic life,
recreation etc. Dissolved oxygen standards are used to assess aquatic life and
pathogen indicators are used to assess recreation for example. Standards
assessment criteria have been developed for each parameter assessed. The
standards assessment criteria are used to make water quality assessments- not the
standards themselves. While the standards assessment criteria are based on the
standards they are different in that a frequency term is included. The details of
how each standard is assessed are discussed in the following sections.
Aquatic Life Assessment Methodology
Numerical Water Quality Standards
The aquatic life numerical water quality standards are assessed using a 10%
exceedance of the standard criterion. These assessments use ambient monitoring
data from the five year assessment period (2004-2008). If no aquatic life
numerical water quality standards exceed the 10% criterion then the AU is
Supporting aquatic life water quality standards. This AU/multiple-parameters
assessment is a Category 1 listing not requiring a TMDL. If greater than 10% of the
NC
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8.15
Page 5 of 14 2010 Integrated Report Methodology EPA Approved 8/31/2010
samples exceed the numerical standard and there are at least 10 samples, then the
AU is Impaired for that parameter. The AU/parameter assessment is listed in
Category 5, requiring a TMDL. If the 10% criterion was exceeded and fewer than
10 samples were collected the AU was Not Rated and targeted for further sampling.
This is a Category 3a listing not requiring a TMDL. The NC DWQ “Redbook”
contains the complete descriptions of water quality standards and surface water
classifications [15a NCAC 02B .0200 - .0300]
Dissolved Oxygen (DO) Standards
Freshwater dissolved oxygen: not less than 6.0 mg/l for trout waters; for non-trout
waters, not less than a daily average of 5.0 mg/l with a minimum instantaneous
value of not less than 4.0 mg/l; swamp waters, lake coves or backwaters, and lake
bottom waters may have lower values if caused by natural conditions.
Salt water dissolved oxygen: not less than 5.0 mg/l, except that swamp waters,
poorly flushed tidally influenced streams or embayments, or estuarine bottom
waters may have lower values if caused by natural conditions.
Freshwater Dissolved Oxygen (DO) Assessment (Class C, B, WS)
A fresh non-swamp water AU was assessed as Impaired for aquatic life when
greater than 10% of samples were below 4 mg/l for instantaneous samples
(monthly) or when greater than 10% of samples are below a daily average of
5mg/l. A minimum of 10 samples was needed to rate the water as Impaired.
Saltwater Dissolved Oxygen (DO) Assessment (Class SC, SB, SA)
A saline/estuarine non-swamp water AU was assessed as Impaired for aquatic life
when greater than 10% of samples were below 5 mg/l. A minimum of 10 samples
was needed to rate the water as Impaired.
Trout Water Dissolved Oxygen (DO) Assessment (Supplemental Class Tr)
A supplemental classified Trout water AU was assessed as Impaired for aquatic life
when greater than 10% of samples were below 6 mg/l. A minimum of 10 samples
was needed to rate the water as Impaired.
Swamp Water Dissolved Oxygen (DO) Assessment (Supplemental Class Sw)
A supplemental classified swamp (Sw) AU was Not Rated for aquatic life when
greater than 10% of samples were below 4 mg/l (5 mg/l for salt) for instantaneous
samples (monthly) or when greater than 10% of samples were below a daily
average of 5 mg/l (freshwater only). There is not a numerical standard for these
waterbodies and natural background conditions cannot be determined. This is a
category 3a listing not requiring a TMDL.
A swamp like AU (not classified Sw) was Not Rated for aquatic life when greater
than 10% of samples were below 4 mg/l (5 mg/l for salt) for instantaneous samples
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(monthly) or when greater than 10% of samples were below a daily average of
5mg/l (freshwater only) and when greater than 10% of samples were below a pH of
6.0 (SU) for freshwater or 6.8 (SU) for saltwater. Geographic location, biological
data, tributary classifications, discharges and land use were considered when
assigning use support ratings to waters considered to be swamp like or receiving
significant swamp water input.
pH
pH Standards
Freshwater pH: shall be normal for the waters in the area, which generally shall
range between 6.0 and 9.0 except that swamp waters may have a pH as low as 4.3
if it is the result of natural conditions;
Saltwater pH: shall be normal for the waters in the area, which generally shall
range between 6.8 and 8.5 except that swamp waters may have a pH as low as 4.3
if it is the result of natural conditions;
Low pH Assessment (Class C, SC, B, SB, SA, WS)
A non-swamp water AU was assessed as Impaired for aquatic life when greater than
10% of samples were below a pH of 6.0 (SU) for freshwater or 6.8 (SU) for
saltwater.
A swamp like AU (not classified Sw) was Not Rated for aquatic life when greater
than 10% of samples were below a pH of 6.0 (SU) for freshwater or 6.8 (SU) for
saltwater or when greater than 10% of samples were below a dissolved oxygen of
4 mg/l (5 mg/l for salt) for instantaneous samples (monthly) or when greater than
10% of samples were below a daily average of 5mg/l (freshwater only) Geographic
location, biological data, tributary classifications, discharges and land use were
considered when making use support determinations on waters considered to be
swamp like or receiving significant swamp water input.
High pH Assessment (Class C, SC, B, SB, SA, WS)
An AU was assessed as Impaired for aquatic life when greater than 10% of samples
were greater than a pH of 9 (SU) for freshwater or 8.5 (SU) for saltwater. A
minimum of 10 samples was needed to rate the water as Impaired. This is a
Category 5 listing requiring a TMDL.
If the 10% criterion was exceeded and fewer than 10 samples were collected the
AU was Not Rated and targeted for further sampling. This is a Category 3a listing
not requiring a TMDL.
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Swamp Water Low pH Assessment (Supplemental Class Sw)
A supplemental classified swamp (Sw) AU was assessed as Impaired when greater
than 10% of samples were below 4.3 (SU). A minimum of 10 samples was needed
to rate the water as Impaired. This is a Category 5 listing requiring a TMDL.
If the 10% criterion was exceeded and fewer than 10 samples were collected the
AU was Not Rated and targeted for further sampling. This is a Category 3a listing
not requiring a TMDL.
Temperature Use Assessment
Temperature Standards
For freshwaters- Temperature: not to exceed 2.8°C (5.04°F) above the natural
water temperature, and in no case to exceed 29°C (84.2°F) for mountain and upper
piedmont waters and 32°C (89.6°F) for lower piedmont and coastal plain waters.
The temperature for trout waters shall not be increased by more than 0.5°C (0.9°F)
due to the discharge of heated liquids, but in no case to exceed 20°C (68°F).
Lower piedmont and coastal plain waters mean those waters of the Catawba River
Basin below Lookout Shoals Dam; the Yadkin River Basin below the junction of the
Forsyth, Yadkin, and Davie County lines; and all of the waters of Cape Fear,
Lumber, Roanoke, Neuse, Tar-Pamlico, Chowan, Pasquotank, and White Oak River
Basins; except tidal salt waters which are assigned S classifications.
Mountain and upper piedmont waters mean all of the waters of the Hiwassee; Little
Tennessee, including the Savannah River drainage area; French Broad; Broad;
New; and Watauga River Basins; and those portions of the Catawba River Basin
above Lookout Shoals Dam and the Yadkin River Basin above the junction of the
Forsyth, Yadkin, and Davie County lines.
For saltwaters- Temperature: shall not be increased above the natural water
temperature by more than 0.8°C (1.44°F) during the months of June, July, and
August nor more than 2.2°C (3.96°F) during other months and in no cases to
exceed 32°C (89.6°F) due to the discharge of heated liquids.
Temperature Assessment
A mountain or upper piedmont AU was assessed as Impaired for aquatic life when
greater than 10% of samples were greater than 29°C. A minimum of 10 samples
was needed to rate the water as Impaired.
A lower piedmont or coastal plain stream AU was assessed as Impaired for aquatic
life when greater than 10% of samples were greater than 32°C. A minimum of 10
samples was needed to rate the water as Impaired.
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If the 10% criterion was exceeded and fewer than 10 samples were collected the
water was Not Rated and targeted for further sampling. This is a Category 3a listing
not requiring a TMDL.
Temperature Screening Criteria for Trout Waters (Supplemental Class
Tr)
A supplemental classified trout water (Tr) AU was Not Rated for aquatic life when
greater than 10% of samples were greater than 20°C. The presence of heated
discharges was not determined. This is a Category 3a listing not requiring a TMDL.
Assessment of Extreme Temperature Conditions
A waterbody that exceeds the above criteria may be Not Rated for aquatic life
because of meteorological conditions that occur on a regular basis. These
conditions must be documented and reassessment will occur after more normal
conditions return. This is a Category 3a listing not requiring a TMDL. Examples of
extreme conditions may include extreme drought, reservoir drawdown, hurricane
impacts and flooding, dam failure, and saltwater encroachment. Other extreme
conditions may be documented as needed for future assessments
Chlorophyll a
Chlorophyll a Standard
Chlorophyll a (corrected): not greater than 40 g/l in sounds, estuaries, and other
waters subject to growths of macroscopic or microscopic vegetation.
Other waters subject to growths are interpreted by DWQ to include dam
backwaters, lakes and reservoirs.
Chlorophyll a Standards Assessment
An AU was assessed as Impaired for aquatic life when greater than 10% of samples
were greater than 40 g/l. A minimum of 10 samples was needed to rate the water
as Impaired. This is a Category 5 listing requiring a TMDL.
If the 10% criterion was exceeded and fewer than 10 samples were collected the
AU was Not Rated and targeted for further sampling. Some reservoirs in North
Carolina are sampled fewer than 10 times during the assessment period. These
data are used to document eutrophication issues. Reservoirs are targeted for
increased monitoring to determine if there are standards violations using the above
methodology. This is a Category 3a listing not requiring a TMDL.
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Toxic Substances and Action Levels Metals
Toxic Substances Numerical Standards
Refer to the NC DWQ “Redbook” for complete text of standards
Arsenic: 50 ug/l
Beryllium: 6.5 ug/l;
Cadmium: 0.4 ug/l for trout waters and 2.0 ug/l for non-trout waters;
Chlorine, total residual: 17 ug/l;
Chromium, total recoverable: 50 ug/l;
Cyanide: 5.0 ug/l
Fluorides: 1.8 mg/l;
Lead, total recoverable: 25 ug/l;
Mercury (assessed in fish consumption category)
Nickel: 88 ug/l; 8.3 ug/l
Chlorides: 230mg/l; (note this is an action level standard)
Metals Action Level Standards
Action Level Copper: 7 ug/l FW or 3 ug/l SW
Action Level Silver: 0.06 ug/l;
Action Level Zinc: 50 ug/l;
Toxic Substances and Action Level Metals Assessment
An AU was assessed as Impaired for aquatic life when greater than 10% of samples
were greater than the above standards or action level standards. A minimum of 10
samples was needed to rate the water as Impaired. These are Category 5 listings
requiring a TMDL.
If the 10% criterion was exceeded and fewer than 10 samples were collected the
AU was Not Rated and targeted for further sampling. This is a Category 3a listing
not requiring a TMDL.
The action level standard for Iron was not assessed during this assessment period
because the standard is being reevaluated and the Iron exceedances of the Action
Level have been shown to be a natural condition.
Action levels are used for permitting purposes and are not used as the only
information to assess aquatic life uses. Copper and Zinc may be indicators of
potential impacts to aquatic life. DWQ will review Copper and Zinc assessments
that result in Category 5 listings. The review will be used to determine if the
Category 5 listing is appropriate. The following criteria will be used to determine if
a review is warranted.
1. A collocated Good, Excellent, Natural or Not Impaired biological rating or
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2. A collocated Good-Fair, Moderate or Not Rated biological rating and less than
25% of Copper or Zinc samples exceed the evaluation level.
3. There are no biological data available and less than 25% of Copper or Zinc
samples exceed the evaluation level.
The Water Quality Assessment Team will evaluate and integrate the following lines
of watershed information to determine if a Category 5 listing for Copper and/or Zinc
is warranted.
1- Analysis of duration, frequency and magnitude of exceedances.
2- Historical data and trends for the parameter of interest.
3- Detailed assessment of all available biological data.
4- Qualitative aquatic habitat information.
5- Natural or background conditions assessment including current imagery.
6- Sample quality (note that Zinc samples can be easily contaminated)
7- Waterbody classifications and other designated uses.
8- Exceedances of other likely associated metals.
9- Biological data in nearby Assessment Units.
10- Potential Sources of metals
11- Site specific hardness
After review the Assessment team will determine if the AU/parameter assessment is
more appropriately listed in a Category other than 5. Each reviewed assessment
will require documented justification for a final Integrate Report category other than
Category 5.
Turbidity
Turbidity Standards
Turbidity: the turbidity in the receiving water shall not exceed 50 Nephelometric
Turbidity Units (NTU) in streams not designated as trout waters and 10 NTU in
streams, lakes or reservoirs designated as trout waters; for lakes and reservoirs not
designated as trout waters, the turbidity shall not exceed 25 NTU; if turbidity
exceeds these levels due to natural background conditions, the existing turbidity
level cannot be increased.
Turbidity Assessment
An AU was assessed as Impaired for aquatic life when greater than 10% of samples
were greater than 50 NTU or 10 NTU for Tr waters or 25 NTU for lakes, reservoirs
and estuarine waters. A minimum of 10 samples was needed to rate the water as
Impaired. This is a Category 5 listing requiring a TMDL.
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If the 10% criterion was exceeded and fewer than 10 samples were collected the
AU was Not Rated and targeted for further sampling. This is a Category 3a listing
not requiring a TMDL.
Ecological/Biological Integrity
Aquatic Life Narrative Standards
The aquatic life narrative water quality standard is assessed using a biological
integrity index criterion (or bioclassification). Biological integrity means the ability
of an aquatic ecosystem to support and maintain a balanced and indigenous
community of organisms having species composition, diversity, population densities
and functional organization similar to that of reference conditions. Waters shall be
suitable for aquatic life propagation and maintenance of biological integrity, wildlife,
secondary recreation, and agriculture. Sources of water pollution which preclude
any of these uses on either a short-term or long-term basis shall be considered to
be violating a water quality standard.
Aquatic Life Assessment
An AU was assessed as Impaired for aquatic life when a fish or benthic
macroinvertebrate community sample received a bioclassification of Severe, Poor or
Fair and there were no other Aquatic Life standards violations. This is a Category 5
listing requiring a TMDL.
An AU was assessed as Impaired for aquatic life when a fish or benthic
macroinvertebrate community sample received a bioclassification of Severe, Poor or
Fair and there were other Aquatic Life numeric standards violations. This is a
Category 4s listing requiring a TMDL for the identified aquatic life numerical
standards violation (Category 5 or 4t listing) impairing the ecological/biological
integrity of the waterbody.
An AU was assessed as Impaired for aquatic life when a fish or benthic
macroinvertebrate community sample received a bioclassification of Severe, Poor or
Fair and an approved TMDL for an aquatic life numerical water quality standard has
been completely implemented. This is a Category 5s listing requiring a TMDL.
Recreation Assessment Methodology
Recreation standards were assessed using fecal coliform bacteria data collected at
DWQ ambient stations and special study sites and enterrococci data collected at
DEH Recreational Monitoring sites in coastal waters. Screening criteria were used
to assess areas for potential standards violations. DEH advisory postings were also
used for recreation assessments as well. The following criteria were used to assess
waters for recreation.
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Pathogen Indicator Standards
Organisms of coliform group: fecal coliforms not to exceed geometric mean of
200/100 ml (MF count) based on at least five consecutive samples examined during
any 30-day period and not to exceed 400/100 ml in more than 20 percent of the
samples examined during such period.
Enterococcus, including Enterococcus faecalis, Enterococcus faecium, Enterococcus
avium and Enterococcus gallinarium: not to exceed a geometric mean of 35
enterococci per 100 ml based upon a minimum of five samples within any
consecutive 30 days.
Fecal Coliform Bacteria Assessment Criteria
An AU was assessed as Impaired when the geometric mean was greater than 200
colonies/100ml or greater than 20% of the samples were higher than 400
colonies/100ml. At least 5 samples must have been collected within the same 30-
day period. This is a Category 5 listing requiring a TMDL.
Fecal Coliform Bacteria Screening Assessment
An AU was Not Rated when the geometric mean was greater than 200
colonies/100ml or greater than 20% of the samples were higher than 400
colonies/100ml. Samples were not collected in the same 30-day period. This is a
Category 3a listing not requiring a TMDL. These AUs are prioritized for resampling
5 times in 30 days based on classification and available resources. Data are
reviewed yearly for prioritization.
Enterrococci Assessment Criteria
An AU was assessed as Impaired when the geometric mean was greater than 35
colonies/100ml. At least 5 samples must have been collected within the same 30-
day period. This is a Category 5 listing requiring a TMDL.
Enterrococcus Screening Assessment
An AU was Not Rated when the geometric mean was greater than 35
colonies/100ml. Samples were not collected in the same 30-day period. This is a
Category 3a listing not requiring a TMDL.
Advisory Posting Assessment
An AU was assessed as Impaired when a swimming advisory was posted for greater
than 61 days in any 5 year period (includes permanent postings). This is a
Category 4cr listing not requiring a TMDL.
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Shellfish Harvesting Assessment Methodology
Shellfish Harvesting standards were assessed using DEH growing area
classifications. The following criteria were used to assess waters for shellfish
harvesting.
Shellfish Harvesting Standards
Organisms of coliform group: fecal coliform group not to exceed a median MF of
14/100 ml and not more than 10% of the samples shall exceed an MF count of
43/100 ml in those areas most probably exposed to fecal contamination during the
most unfavorable hydrographic and pollution conditions.
Fecal Coliform Bacteria Assessment Criteria
DEH fecal coliform data were not assessed to determine standards violations.
Category 5 impairments were based on Growing Area Classifications alone.
DEH Shellfish Sanitation Growing Area Classification Assessment
An AU was assessed as Impaired when the DEH growing area classification was
Prohibited or conditionally approved. This is a Category 5 listing requiring a TMDL.
Water Supply Assessment Methodology
Water Supply standards were assessed using data collected at DWQ ambient
stations located in Class WSI-WSV waters. The following criteria were used to
Impair waters for water supply. Category 5 listings were only made when
Standards Assessment Criteria (SAC) were exceeded.
Water Supply Standards
Refer to Water Quality “Redbook” for complete text of standards
Barium: 1.0 mg/l;
Chloride: 250 mg/l;
Manganese: 200 ug/l; (not human health or aquatic life- not assessed)
Nickel: 25 ug/l;
Nitrate nitrogen: 10.0 mg/l;
2,4-D: 100 ug/l;
2,4,5-TP (Silvex): 10 ug/l;
Sulfates: 250 mg/l;
Water Supply Assessment
An AU was assessed as Impaired for water supply when greater than 10% of
samples were greater than the above standards except for manganese. A minimum
of 10 samples was needed to rate the water as Impaired. This is a Category 5
listing requiring a TMDL.
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If the 10% criterion was exceeded and fewer than 10 samples were collected the
AU was Not Rated and targeted for further sampling. This is a Category 3a listing
not requiring a TMDL.
Fish Consumption Assessment Methodology
Fish Consumption was assessed based on site-specific fish consumption advisories.
The advisories were based on the NC Department of Health and Human Services
(DHHS) consumption advisories developed using fish tissue data that exceed
standards. The following criteria were used to Impair waters for fish consumption.
Because of the statewide Mercury advice there were no use cases for Supporting
fish consumption and therefore no overall Category 1 waters.
Polychlorinated biphenyls (PCBs) Assessment Criteria
An AU was assessed as Impaired when a site-specific advisory was posted for PCBs.
This is a Category 5 listing requiring a TMDL.
Dioxin Assessment Criteria
An AU was assessed as Impaired when a site-specific advisory was posted for
dioxins. This is a Category 5 listing requiring a TMDL.
Mercury Assessment Criteria
An AU was assessed as Impaired for fish consumption when greater than 10% of
samples were greater than 0.012 g/l. A minimum of 10 samples was needed to
rate the water as Impaired. This is a Category 5 listing requiring a TMDL.
If the 10% criterion was exceeded and fewer than 10 samples were collected the
AU was Not Rated and targeted for further sampling. This is a Category 3a listing
not requiring a TMDL.
Statewide advice for Mercury in fish tissue was not assessed because it was not
associated with a specific AU but was applied to all waters of the state. All AUs are
considered Impaired and in Category 5 for the statewide Mercury fish consumption
advice. Previous site specific listings for Mercury will no longer be listed in Category
5. DWQ continues to monitor mercury in fish tissue, and has identified specific
locations where Mercury levels exceed 0.4mg/kg of fish tissue.