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N.C. Department of Environment and Natural Resources

NC Department of Environment and Natural Resources
Water Quality - Surface Water Triennial Review

Water Quality


DOWNLOAD: Proposed Draft Amendments April 2014 

Under the Federal Water Pollution Control Act (the Clean Water Act)

( NC is delegated the authority to establish the water body classifications and applicable water quality standards to protect human health and the aquatic environment. Per this delegation, the state is expected to adopt water quality standards (WQS), which include numeric and narrative criteria and designated use classifications, as well as antidegradation provisions, to protect all uses of the waters of the state.  Requirements to establish these standards is authorized to the Environmental Management Commission (EMC) by NC General Statutes (NC GS §143-214.1 and 215.3(a)). Water quality standards are used in various ways such as setting NC’s National Pollutant Discharge Elimination System (NPDES) permit limits and evaluating the conditions of the surface waters of the state per Clean Water Act Sections 303(d) and 305(b).

Every three years the State is required to review its surface water quality standards, classifications and applicable variances to determine if changes are needed and, if necessary, to make those changes. This review process is called the "Triennial Review."  A Notice of Hearing for the Triennial Review was published in the November 1, 2013 edition of the North Carolina Register. Additionally, notice was made to the public via the Division of Water Resources (DWR) website. On behalf of the EMC, the DWR held a public hearing on November 19th, 2013 in Raleigh to seek comments on potential revisions to the water quality regulations in Title 15A NCAC 02B .0100-.0110, .0201-.0228, .0230-.0231 and .0300-.0317 located at  15A NCAC 02B Regulations. Mr. Steve Tedder, Chairman of the Water Quality Committee (WQC) of the EMC, was the EMC appointed Hearing Officer. Public comments were accepted through the close of the public comment period (January 3, 2014). Approximately 100 individuals attended the public hearing, with 32 requesting to comment. Approximately 1,900 written comments were received. They included nearly 1,860 e-mails and letters from individuals; approximately 20 from business and industries, local governments, representatives of local governments and agricultural interests; approximately 15 from non-governmental organizations; two from federal government representatives and three letters addressing water quality variances specifically.  Written comments are accessible online (Public Comments - Written Submittals). 

Comments from all parties were considered and reviewed by the Hearing Officer, and by DWR staff, for potential modifications to the 15A NCAC 02B regulations. Although submitted comments were varied in nature and extent, commenters, on the whole, voiced support of modifying and updating the water quality standards to maintain and protect North Carolina’s waters.  After careful deliberation, Mr. Tedder presented his findings to the EMC (March 2014). The following recommendations were made for staff to evaluate as they draft proposed changes to the 15A NCAC 02B regulations:  

Chlorophyll a:  

Retain current Chlorophyll a standards.  

Metals Standards: 

Replace existing Total Recoverable Metals standards with Dissolved Metal standards.

Adopt the current Aquatic Life protective National Recommended Water Quality Criterion for dissolved metals, as acute and chronic criterion for the following:

• Arsenic,

• Copper,

• Nickel,

• Silver,

• Lead,

• Chromium III, and

• Chromium VI.

Allow use of the Biotic Ligand Model as published by the US EPA for the recalculation of Aquatic Life protective criteria for Copper (Acute and Chronic).
•Adopt the Aquatic Life protective recalculated National Recommended Water Quality Criterion for the dissolved form of Cadmium (Acute and Chronic).
Maintain current:

• Total recoverable Mercury standard,
• Total recoverable Selenium standard, and
•  Reevaluate both during next Triennial Review. 

Consider deletion of existing water quality standards for:

• Total Chromium,
•  Manganese, and
•  Iron. 

Where applicable, adopt equation-based water quality standards for dissolved metals.

For equation-based hardness dependent metals, propose instream water quality criteria to be calculated from no less than 25 mg/L to no greater than 400 mg/L hardness.

With the exception of Mercury and Selenium, allow careful consideration of aquatic life biological integrity to take precedence over ambient standard violations for water quality assessment purposes.

For assessment clarity, define sampling protocol for instream monitoring of acute and chronic dissolved metals.

 • NPDES Permitting Provisions: 

Codify the use of 1Q10 stream flows for implementation of acute water quality standards in NPDES permitting.

Allow the use of the median instream hardness values in calculating permit limits based on the proposed hardness-dependent metals standards. 

Specify that the median instream hardness values used in the NPDES permit calculations will be based upon the data contained in the US EPA STORET Data Warehouse within the local US Geological Survey and Natural Resource Conservation Service 8-digit Hydrologic Unit (subbasin level).   

Retain the Action Level regulations for copper, silver, zinc, and chloride.

 • Variances:

Comments related to facility-specific water quality standards variances shall be considered at permit renewal by DWR staff and the NPDES Committee of the EMC.  A list of current variances is located here: 2013 WQS Variance List (As of 10/15/2013)


In compliance with the Hearing Officer and EMC’s recommendations, the following is a summary of changes to be proposed in May at the Water Quality Committee meeting. Staff will request permission to proceed to the EMC to request permission to hold public hearings on these proposed rule amendments. As proposed changes to water quality standards regulations resulting from these hearings could affect permitting, monitoring, and assessment programs, a fiscal note has been prepared. The draft Fiscal Note has been submitted to the Office of State Budget Management (OSBM)  to review proposed 15A NCAC 02B rule changes based on the NC Administrative Procedures Act, Chapter 150B of the General Statutes (GS § 150B) and State of North Carolina Executive Order No. 70, using the guidance and policy as provided in the State Budget Manual. Division staff previously requested public input and cost and benefit information from potentially affected parties in order to facilitate this process.  

An overview of the chemicals examined for this Triennial Review follows: 


Summary of Proposed Metals Changes 
Proposed revisions to metals standards are summarized in the attached “
Metals Summary Table” for quick reference. Modifications to standards reflect: updates to National Recommended Water Quality Criterion (NRWQC); revision of metals standards to reflect, where appropriate, the dissolved metal concentration; the addition of acute and chronic standards; and for hardness dependent metals, equation based standards applicable to a range of specific instream hardnesses from 25 mg/l to 400 mg/L. 

National Recommended Water Quality Criterion Updates
Staff has compared the US EPA NRWQC values for metals to existing North Carolina standards and identified parameters requiring modifications.

Dissolved Metals
Freshwater and saltwater criteria for most metals can be expressed as the total recoverable metal or the dissolved metal in the water column. With the exception of Mercury and Selenium, which are both bioaccumulative metals, the State proposes changing to dissolved metal water quality standards. The dissolved fraction more closely estimates the portion of the metal that is toxic to aquatic life.  

Dissolved metals are calculated by using the applicable aquatic life criteria expressed in terms of total recoverable metal, and multiplying it by a conversion factor. A conversion factor accounts for the laboratory testing differences used to establish the original federal aquatic life criteria. The Conversion Factor for each metal can be viewed at the US EPA website, see “Appendix A - Conversion Factors for Dissolved Metals” 

Acute and Chronic Aquatic Life Standards 
North Carolina currently has chronic aquatic life water quality standards for metals. Chronic standards offer protection from toxic effects resulting from long-term exposure to a chemical. With the exception of Mercury and Selenium, addition of standards protective of acute (or short term) exposure will be proposed. Incorporation of standards for “acute” impacts will remove the "maximum permissible level" language from the aquatic life standards (15A NCAC 02B .0211(3)(l) and 15A NCAC 02B .0220(3)(m)). An acute standard will be expressed as an average of two or more samples collected within one hour. Chronic standards will be expressed as a minimum of four samples taken on consecutive days, or as a 96 hour average concentration.   

Hardness-Dependent Metals 
Various components of water quality such as naturally occurring organic matter, pH, hardness, alkalinity and sodium can affect metal toxicity. When evaluating the toxicity of metals to aquatic life, “hardness-dependent” means that the toxicity of the chemical increases as the hardness of the receiving water decreases. The EPA establishes hardness-dependent water quality standards, in the form of equations, for the protection of freshwater aquatic life for the following metals: Copper, Zinc, Cadmium, Nickel, Chromium III, Silver and Lead. 

The State previously assigned a statewide hardness of 50 mg/l when calculating numerical hardness-dependent water quality standards. This value equaled the mean of hardness data collected by the State of North Carolina at all sampling sites across the state. Because surface water hardness varies throughout the state, NC reviewed analytical hardness values for subbasins within the state to assure protection of sensitive species as directed by national protocol. This data evaluation indicated that a significant portion of the state periodically has hardness values at or near 25 mg/L. For illustrative purposes, the proposed regulations provide a table of calculated water quality standards for hardness-dependent metals at a hardness of 25 mg/L.   

In addition, the proposed regulations include hardness-dependent equations to allow flexibility for other, more regionally specific, hardness values to be applied. Application of the equations requires the incorporation of hardness values based on the 50th percentile of data collected within the local US Geological Survey (USGS) 8-digit Hydrologic Unit (HU). The equations are applicable for instream hardness ranges from 25 mg/l to 400 mg/l, expressed as CaCO3 or Ca+Mg.   

The US EPA continues to examine the impact of other water quality components on metals toxicity. EPA has published only one revised criterion, for copper, which establishes a model used to determine copper toxicity based on a broad set of water quality parameters. The State proposes allowance for the use of the Copper Biotic Ligand Model in accordance with this revised federal criterion.  

Naturally Occurring Iron and Manganese
The State proposes to remove the standards for iron and manganese. Iron and Manganese are naturally occurring metals in the sediments and groundwater of the state. 

Attainment of Aquatic Life Uses
The State proposes regulatory language relating to the demonstration of aquatic life use attainment with respect to metals standards. 

2, 4 D (chlorophenoxy herbicide) 

The US EPA Integrated Risk Information System (IRIS) has toxicity information with respect to the non-carcinogenic effects of 2, 4 D. North Carolina is proposing to revise the human health standard applicable to water supplies, currently 100 ug/l, to include this toxicity information. Incorporation of the new toxicity information results in a reduction in the water supply standard to 70 ug/l. 

Schedule of the Triennial Review of Surface Water Quality Standards

  • November 19, 2013:

Public Hearing on Triennial Review
Comments Received

  •  March 13, 2014:

Environmental Management Commission (EMC) information item. Presentation of Hearing Officer’s Report of Proceedings and recommendations to staff. 
  • March – April 2014:

Develop draft rule package for presentation to the Water Quality Committee (WQC) in May of 2014. 
  • May 2014:

WQC Action Item: Request approval of proposed amendments to water quality standards regulations to proceed to the EMC to take changes out to public notice and public hearing. Additionally, request approval to proceed to the EMC with the Fiscal Analysis prepared under GS 150B.
EMC Action Item: Staff request permission to proceed to public hearing on proposed amendments and Fiscal Analysis. 
  • June 2014:

North Carolina Register notification of Public Hearings/60 day Comment Period.  


  • July 2014:  Conduct Public Hearings.

 Public Hearing:
 Date:  Tuesday, July 15th, 2014
 Time: 2:00 PM
 Location:  Ground Floor Hearing Room, Archdale Building, 512 N. Salisbury St., Raleigh, NC


 Public Hearing:

 Date:  Wednesday, July 16th, 2014
 Time: 3:00 PM
 Location:  Statesville Civic Center, 300 South Center Street, Statesville,  NC

Submission of Comments:  All written comments, data or relevant information received by 5:00 PM, Friday, August 22, 2014 will be considered and included in this Triennial Review hearing record. 
Please submit to:  
Connie Brower
DENR/Division of Water Resources/Water Planning Section
1611 Mail Service Center
Raleigh, NC 27699-1611
By fax: (919) 807-6497
Additional questions should be directed to:
Connie Brower
(919) 807-6416
August 2014: End of Comment Period 5:00 PM, Friday, August 22, 2014
  • August 2014-September 2014:

Review of comments received; Hearing Officer prepares report of proceeding for submission to the EMC.
  • November 2014/ January 2015:

EMC Action Item: Hearing Officer’s Report of Proceedings and recommendations to the EMC for adoption of revised water quality standards.
  • January 2015-March 2015:

Pending approval by EMC to adopt proposed rule, rules submitted to Office of Administrative Hearings, Rules Review Commission (RRC).
Rule amendments reviewed by the RRC. 



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