Chapter 4 Classifications

Chapter 4
North Carolina Water Quality Classifications and Standards

4.1 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 by 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).

4.1.1 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 10 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 (Administrative Code 15A NCAC 2B .0200). Information is also available on
DWQ’s website http://h2o.enr.state.nc.us/csu/.

4.1.2 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 118.6 stream miles of HQW waters in the New River basin (Figure 8). Special HQW
protection management strategies are intended to prevent degradation of water quality below
present levels from both point and nonpoint sources. The HQW designation requires new
wastewater discharge facilities and facilities that are expanding beyond their current permitted
loadings address oxygen-consuming wastes, total suspended solids, disinfection, emergency
requirements, volume, nutrients (in nutrient sensitive waters) and toxic substances.
Chapter 4 – North Carolina Water Quality Classifications and Standards 53

Table 10 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 drain to and are within one mile of
HQWs and which require (1) a Sedimentation and
Erosion Control Plan in accordance with rules
established by the NC Sedimentation Control
Commission or (2) an approved local erosion and
sedimentation control program must control runoff
using either a low-density or high-density
development 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 (i.e., stormwater infiltration system, wet
detention ponds). 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.
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.

Chapter 4 – North Carolina Water Quality Classifications and Standards 54

Outstanding Resource Waters (Class ORW)
There are 71.0 stream miles of ORW waters
in the New River basin (Figure 8). These
waters have excellent water quality (rated
based on biological and chemical sampling
as with HQWs) and an associated
outstanding resource.

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 Administrative Code
15A NCAC 2B .0225. At a minimum, no new discharges or expansions are permitted, and a 30-
foot vegetated buffer or stormwater controls are required for new developments. 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 (Section
4.1.3).
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.

Primary Recreation (Class B)
There are 120.4 stream miles classified for primary recreation in the New 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 much be treated to avoid potential impacts to the existing
water quality.

Trout Waters
There are 614.7 stream miles classified as trout (Tr) waters in the New River basin. Different
water quality standards for some parameters, such as dissolved oxygen, temperature and
turbidity, have been developed to protect freshwaters for natural trout propagation and survival
of stocked trout. These water quality standards result in more restrictive limits for wastewater
discharges to trout waters.

There are no watershed development restrictions associated with the trout classification;
however, the NC Division of Land Resources (DLR), under the NC Sedimentation and Pollution
Control Act (SPCA), has requirements to protect trout streams from land-disturbing activities.
Under General Statute 113A-57(1), “waters that have been classified as trout waters by the
Environmental Management Commission (EMC) shall have an undisturbed buffer zone 25 feet
wide or of sufficient width to confine visible siltation within the twenty-five percent of the buffer
zone nearest the land-disturbing activity, whichever is greater.” The Sedimentation Control
Commission, however, can approve land-disturbing activities along trout waters when the
duration of the disturbance is temporary and the extent of the disturbance is minimal. This rule
also applies to unnamed tributaries flowing to the affected trout water stream. Further
clarification on classifications of unnamed tributaries can be found under Administration Code
15A NCAC 02B .0301(i)(1). For more information regarding land-disturbing activities along
designated trout streams, see the DLR website at http://www.dlr.enr.state.nc.us/.

The NC Wildlife Resources Commission (WRC) administers a state fishery management
classification, Designated Public Mountain Trout Waters. It provides for public access to
streams for fishing and regulates fishing activities (seasons, size limits, creel limits, and bait
Chapter 4 – North Carolina Water Quality Classifications and Standards 55

and lure restrictions). Although many of these waters are also classified Tr by DWQ, this is not
the same classification.

Water Supply Watersheds (Class WS)
There are 145.9 freshwater stream miles currently classified for water supply in the New River
basin (Figure 9). The purpose of the Water Supply Watershed Protection Program is to provide a
proactive drinking water supply protection program for communities. Local governments
administer the program based on state minimum requirements. There are restrictions on
wastewater discharges, development, landfills and residual application sites to control the
impacts of point and nonpoint sources of pollution to water supplies.

There are five water supply classifications (WS-I to WS-V) that are defined according to the land
use characteristics of the watershed. The WS-I classification carries the greatest protection for
water supplies. No development is allowed in these watersheds. Generally, WS-I lands are
publicly owned. WS-V watersheds have the least amount of protection and do not require
development restrictions. These are either former water supply sources or sources used by
industry. WS-I and WS-II classifications are also HQW by definition because requirements for
these levels of water supply protection are at least as stringent as those for HQWs. Those
watersheds classified as WS-II through WS-IV require local governments having jurisdiction
within the watersheds to adopt and implement land use ordinances for development that are at
least as stringent as the state’s minimum requirements. A 30-foot vegetated setback is required
on perennial streams in these watersheds. The New River basin currently contains WS-II and
WS-IV water supply watersheds (Figure 9).

4.1.3 Special Management Strategies

In the New River basin, there are 678.6 stream miles subject to special management strategies.
Waters under special management strategies are designated with a “+” symbol in the stream
classifications schedule. Under these strategies, stormwater controls are required on land within
one mile of and draining to the designated ORW areas. Discharge limitations also apply to the
“+” designated waters. These limitations were developed using most of the HQW management
strategies as a framework. A summary of the special management strategies for HQW and ORW
waters can be found in Chapter 1. Detailed information can be found in the document entitled
Classifications and Water Quality Standards Applicable to Surface Waters and Wetlands of
North Carolina (NCDENR-DWQ, August 2004a). This document is available on-line at
http://h2o.enr.state.nc.us/csu/.

4.1.4 Reclassification of Surface Waters

The classification of a surface water may be changed after a request is submitted to the DWQ
Classifications and Standards Unit. DWQ reviews each request for reclassification and conducts
an assessment of the surface water to determine if the reclassification is appropriate. If it is
determined that a reclassification is justified, the request must proceed through the state rule-
making process. To initiate a reclassification, the “Application to Request Reclassification of
NC Surface Waters” must be completed and submitted to DWQ’s Classifications and Standards
Unit. For more information on requests for reclassification and contact information, visit
http://h2o.enr.state.nc.us/csu/.
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