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Bioassessment and Biocriteria Program Status for South Carolina: Streams and Wadeable Rivers

State Program Contact

South Carolina SEHC Surface Water Quality Exit
Water Quality Standards in South Carolina Exit

Water Quality Standards

WQS Information
The link to South Carolina's WQS that are in effect for Clean Water Act purposes is provided. These are the WQS approved by EPA.
The state of South Carolina provided information and links to sections of their administrative code on designated aquatic life use, biological criteria, antidegradation as well as technical support documents and information on its bioassessment and biocriteria programs. These are included for your convenience and may or may not reflect the most recently EPA approved WQS. The following links exit the site Exit

You may need a PDF reader to view some of the files on this page. Refer to EPA’s about PDF page to learn more.

Designated Aquatic Life Uses
All water use classifications protect for a balanced indigenous aquatic community of fauna and flora. In addition, Trout Natural and Trout Put, Grow, and Take classifications protect for reproducing trout populations and stocked trout populations, respectively.

Biological Criteria
__X__ Narrative, with assessments based in part on numeric values
_____ Numeric
_____ No criteria

South Carolina DHEC R.61-68, Water Classifications and Standards (PDF) (62 pp, 690 K)

Antidegradation Policy
South Carolina DHEC R.61-68, Water Classifications and Standards (PDF) (62 pp, 690 K) (Page 10)

2. Where surface water quality exceeds levels necessary to support propagation of fish, shellfish, and wildlife, and recreation in and on the water, that quality shall be maintained and protected unless the Department finds, after intergovernmental coordination and public participation, that allowing lower water quality is necessary to important economic or social development in the areas where the waters are located.                           

4. Certain natural conditions may cause a depression of dissolved oxygen in surface waters while existing and classified uses are still maintained. The Department shall allow a dissolved oxygen depression in these naturally low dissolved oxygen waterbodies as prescribed below pursuant to the 13 Act, Section 48-1-83, et seq., 1976 Code of Laws:

a. Under these conditions the quality of the surface waters shall not be cumulatively lowered more than 0.1 mg/l for dissolved oxygen from point sources and other activities, or
b. Where natural conditions alone create dissolved oxygen concentrations less than 110 percent of the applicable water quality standard established for that waterbody, the minimum acceptable concentration is 90 percent of the natural condition. Under these circumstances, an anthropogenic dissolved oxygen depression greater than 0.1 mg/l shall not be allowed unless it is demonstrated that resident aquatic species shall not be adversely affected. The Department may modify permit conditions to require appropriate instream biological monitoring.
c. The dissolved oxygen concentrations shall not be cumulatively lowered more than the deficit described above utilizing a daily average unless it can be demonstrated that resident aquatic species shall not be adversely affected by an alternate averaging period.

Biological Assessment

What biological assemblages are used in the bioassessment program?
Benthic macroinvertebrates, fish, phytoplankton, and chlorophyll

Are bioassessments used to support 303(d) listings?
Yes. Listing methodology: Impaired Waters and Contaminant Limits - 303(d), TMDL (PDF) (110 pp, 3 MB)

How are assemblages used to make impairment decisions?
Refer to most current revision of SCDHEC’s aquatic science programs webpage for Technical Reports and Standard Operating Procedures.

Other uses of biocriteria or bioassessment within the water quality program:
Antidegradation, 305(b) surface water condition assessments, TMDL development and assessment, non-point source assessments, BMP evaluation, and restoration goals

Technical Support Information and Documents:

Reference condition:
  • Outstanding National Resource Waters: Exceptional national recreational and/or ecological resource.
  • Outstanding Resource Waters: Exceptional recreational and/or ecological resource and suitable for drinking water source with minimal treatment.
  • No degradation of existing uses is permitted regardless of classification and no degradation of natural conditions is allowed in Outstanding Resource Waters or Outstanding National Resource Waters.

Technical reference material:
Impaired Waters and Contaminant Limits - 303(d), TMDL

Not available.

Stressor identification/causal analysis approach:
Not applicable.

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