Chapter 8

DRAFT Water Quality Classifications and Standards 109
Chapter 8
North Carolina Water Quality Classifications and Standards

8.1 Description of Surface Water Classifications and Standards

North Carolina’s Water Quality Standards Program adopted classifications and water quality
standards for all the state’s river basins in 1963. The program remains consistent with the
Federal Clean Water Act and its amendments. Water quality classifications and standards have
also been modified to promote protection of surface water supply watersheds, high quality waters
(HQW), and unique and special pristine waters with outstanding resource values (ORW).

8.1.1 Statewide Classifications

All surface waters in the state are assigned a primary classification that is appropriate to the best
uses of that water. In addition to primary classifications, surface waters may be assigned a
supplemental classification. Most supplemental classifications have been developed to provide
special protection to sensitive or highly valued resource waters. Table 21 briefly describes the
best uses of each classification. A full description is available in the document titled:
Classifications and Water Quality Standards Applicable to Surface Waters and Wetlands of
North Carolina (NCDENR-DWQ, 2004). Information on this subject is also available at DWQ’s
website: http://h2o.enr.state.nc.us/csu/.

8.1.2 Statewide Water Quality Standards

Each primary and supplemental classification is assigned a set of water quality standards that
establish the level of water quality that must be maintained in the waterbody to support the uses
associated with each classification. Some of the standards, particularly for HQW and ORW
waters, outline protective management strategies aimed at controlling point and nonpoint source
pollution. These strategies are discussed briefly below. The standards for C and SC waters
establish the basic protection level for all state surface waters. The other primary and
supplemental classifications have more stringent standards than for C and SC, and therefore,
require higher levels of protection.

Some of North Carolina’s surface waters are relatively unaffected by pollution sources and have
water quality higher than the standards that are applied to the majority of the waters of the state.
In addition, some waters provide habitat for sensitive biota such as trout, juvenile fish, or rare
and endangered aquatic species.

High Quality Waters (Class HQW)
There are 395,269 acres of HQW waters in the Pasquotank River basin (Figure 10). Special
HQW protection management strategies are intended to prevent degradation of water quality
below present levels from both point and nonpoint sources. HQW requirements for new
wastewater discharge facilities and facilities, which expand beyond their currently permitted
loadings, address oxygen-consuming wastes, total suspended solids, disinfections, emergency
requirements, volume, nutrients (in nutrient sensitive waters) and toxic substances.
110 DRAFT Water Quality Classifications and Standards
Table 21 Primary and Supplemental Surface Water Classifications
PRIMARY FRESHWATER AND SALTWATER CLASSIFICATIONS
Class* Best Uses
C and SC Aquatic life propagation/protection and secondary recreation.
B and SB Primary recreation and Class C and SC uses.
SA Suitable for commercial shellfish harvesting and SB and SC uses.
WS Water Supply (WS): Assigned to watersheds based on land use characteristics. The WS classifications have
management strategies to protect the surface water supply. For WS-I through WS-IV, these include limits on
point source discharges and local programs to control nonpoint source and stormwater runoff. A WS Critical
Area (CA) has more stringent protection measures and is designated within one-half mile from a WS intake
or WS reservoir. All WS classifications are suitable for Class C uses.
WS-I Generally located in natural and undeveloped watersheds.
WS-II Generally located in predominantly undeveloped watersheds.
WS-III Generally located in low to moderately developed watersheds.
WS-IV Generally located in moderately to highly developed watersheds.
WS-V Generally upstream of and draining to Class WS-IV waters. No categorical restrictions on watershed
development or treated wastewater discharges.
SUPPLEMENTAL CLASSIFICATIONS
Class Best Uses
Sw Swamp Waters: Waters that have low velocities and other natural characteristics that are different from
adjacent streams (i.e., lower pH, lower levels of dissolved oxygen).
Tr Trout Waters: Provides protection to freshwaters for natural trout propagation and survival of stocked trout.
HQW High Quality Waters: Waters that have excellent water quality, primary nursery areas and other functional
nursery areas, WS-I and WS-II or SA waters.
ORW Outstanding Resource Waters: Unique and special waters of exceptional state or national recreational or
ecological significance which require special protection.
NSW Nutrient Sensitive Waters: Waters subject to excessive plant growth and requiring limitations on nutrient
inputs.
* Primary classifications beginning with "S" are assigned to saltwaters.

For nonpoint source pollution, development activities which
require a Sedimentation and Erosion Control Plan in
accordance with rules established by the NC Sedimentation
Control Commission or an approved local erosion and
sedimentation control program, and which drain to and are
within one mile of HQWs, are required to control runoff
from the development using either a low density or high
density option. The low-density option requires a 30-foot
vegetated buffer between development activities and the
stream; whereas, the high-density option requires structural
stormwater controls. In addition, the Division of Land
Resources (DLR) requires more stringent erosion controls for
land-disturbing projects within one mile of and draining to
HQWs.

Outstanding Resource Waters (Class ORW)
There are 485 miles, 15,938 freshwater acres, and 43,154 saltwater acres of ORW waters in the
basin (Figure 10). These waters have excellent water quality (rated based on biological and
chemical sampling as with HQWs) and an associated outstanding resource.

Criteria for HQW Classification
• Waters rated as Excellent based on
DWQ’s chemical and biological
sampling.
• Streams designated as native or special
native trout waters by the Wildlife
Resources Commission (WRC).
• Waters designated as primary nursery
areas or other functional nursery areas
by the Division of Marine Fisheries.
• Waters classified by DWQ as WS-I,
WS-II or SA.

DRAFT Water Quality Classifications and Standards 111
The requirements for ORW waters are more
stringent than those for HQWs. Special protection
measures that apply to North Carolina ORWs are
set forth in 15A NCAC 2B .0225. At a minimum,
no new discharges or expansions are permitted, and
a 30-foot vegetated buffer or stormwater controls
for new developments are required. In some
circumstances, the unique characteristics of the
waters and resources that are to be protected require
that a specialized (or customized) ORW
management strategy be developed.

Class SA Waters
There are 395,236 acres of SA waters in the basin. The best uses of Class SA waters are for
shellfishing for market purposes and any other usage specified by the "SB" or "SC"
classification. Fecal coliform bacteria in class SA waters shall meet the current sanitary and
bacteriological standards as adapted by the Commission for Health Services. Domestic
wastewater discharges are not allowed, and there are provisions for stormwater controls. Refer
to 15A NCAC 2B .0221 for specifics on water quality standards in Class SA waters. All Class
SA waters are also carry a supplemental designation of HQW or ORW by rule (see above),
depending on the resource value present at the time of classification.

Primary Recreation (Class B and SB)
There are 25 freshwater miles, 15,938 freshwater acres, 111 saltwater miles, and 312,119
saltwater acres classified for primary recreation in the Pasquotank River basin. Waters classified
as Class B are protected for primary recreation, include frequent and/or organized swimming,
and must meet water quality standards for fecal coliform bacteria. Sewage and all discharged
wastes into Class B waters must be treated to avoid potential impacts to the existing water
quality.

Aquatic Life Propagation and Secondary Recreation (Class C and SC)
There are 3,595 freshwater miles, 4,981 freshwater acres, 12 saltwater miles, and 374,818
saltwater acres classified for aquatic life propagation/protection and secondary recreation in the
Pasquotank River basin.

Swamp Waters (Class Sw)
There are 3,159 freshwater miles, 20,918.9 freshwater acres, 8.8 saltwater miles, and 66,519
saltwater acres with the supplemental classification of swamp waters in the basin. Waters with
this supplemental classification will naturally be more acidic (have lower pH values) and have
lower levels of dissolved oxygen.

Water Supply watershed (Class WS)
There are 54 miles of waters classified as water supply waters. WS classifications are assigned to
watersheds based on land use characteristics of the area. Each water supply classification has a
set of management strategies to protect the surface water supply. There are five WS classes
ranging from WS-I through WS-V; only levels III, IV and V occur in the Pasquotank basin. WS-
I provides the highest level of protection and WS-IV provides the least protection. A Critical
Area (CA) designation is also listed for watershed areas within a half-mile and draining to the
water supply intake or reservoir where an intake is located.
The ORW rule defines outstanding
resource values as including one or more of
the following:
• an outstanding fisheries resource;
• a high level of water-based recreation;
• a special designation such as National Wild
and Scenic River or a National Wildlife
Refuge;
• within a state or national park or forest; or
• a special ecological or scientific
significance.
CURRITUCKCAMDEM
PASQUOTANK
GATES
PERQUIMANS
CHOWAN
WASHINGTON
TYRRELL
DARE
Elizabeth City
Winfall
Hertford
Manteo
Columbia
Roper
Creswell
03-01-54
03-01-50
03-01-52
03-01-53
03-01-51
03-01-56
03-01-55
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Figure 10 HQW, ORW, SA and WSWS waters in the Pasqotank River Basin
0 7 14 21 283.5
Miles
®
Planning Section
Basinwide Planning Unit
May 2, 2007
Southern Shores
Kitty Hawk
Kill Devil Hills
Nags Head
Legend
Subbasin Boundary
Water Supply
Watersheds
WS-IV
ORW
SA
Municipality
County Boundary
Hydrography