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Impaired Waters Determinations Need More Detail, Flexibility

November 29, 2012

A document outlining the process of making impaired waters determinations needed more detail and flexibility, the League wrote in comments submitted November 26. The League's suggestions came in response to a public comment period on the document, called the "use assessment methodology." State regulators use the methodology along with water quality data and standards to determine whether or not waters are impaired.

Given the consequences to municipalities of having a water body included on the state's impaired waters list, the League had long urged a public forum to discuss the adequacy of the methodology. Previously, decisions regarding the methodology were made by N.C. Division of Water Quality (DWQ) staff members without guidance or input from the N.C. Environmental Management Commission (EMC) and with only limited comment from the public.

In response, the EMC decided last month to oversee development of the list, capping an eighteen-month campaign by the League and other stakeholder groups seeking a new process. EMC oversight of development of this list had been a top regulatory priority for the League. (Read more about the League's efforts to secure EMC involvement in "EMC Agrees to Oversee Impaired Waters List" in the November 2012 edition of EcoLINC.)

The state's impaired waters list, also known as the 303(d) list, is named after Section 303(d) of the federal Clean Water Act and is updated every two years. For each two-year cycle, the federal law requires states to evaluate the health of their waters and “list” those exhibiting impairments. Impaired waters most often become subject to a “water pollution diet” for the affected watershed, usually in the form of a Total Maximum Daily Load (TMDL). Local governments, as the holders of wastewater and stormwater discharge permits, bear responsibility for reducing their discharges to waters under a TMDL – often a costly requirement.

NCLM Comments Stressed Lack of Detail, Flexibility

Overall, the League's comments made suggestions to improve the lack of detail and flexibility for decision-makers who determine whether to list waters as impaired. The current methodology did not offer enough description of the process and basis for these important regulatory decisions. Without a complete understanding of the determinations, the public and affected entities such as cities and towns faced difficulties in responding to listing decisions.

Specifically, the League comments offered four over-arching suggestions:

  • Expanding the methodology to include a more complete description of DWQ staff deliberations on listing decisions and to establish reasonable "best professional judgment" guidelines.
  • Requiring a written explanation to accompany each listing decision, including all pertinent information that informed the listing decision.
  • Allowing increased flexibility for decisions, particularly when a decision has a large regulatory impact such as affecting an entire watershed.
  • Including a process to "de-list" waters for good cause, including if mistakes have been made in previous listings or if a study reevaluated the waters and pointed to non-impairment.

The League also offered specific comments on a dozen different aspects of the methodology. Highlights of these specific comments include:

  • Urging more thorough study of data prior to making a listing decision based on chlorophyll a, a parameter indicating nutrient impairment of waters.
  • Reforming the basis upon which fish consumption advisories may be used in impairment decisions, a response to shortcomings in the methodology that surfaced with the mercury TMDL issue earlier this year.
  • Detailing the steps an interested party must take to submit its own water quality sampling data.

In support of its points, the League included information regarding the processes followed by other southeastern states.

Next Up: EMC Approval of List

Under the process recently approved by the EMC, for the next 303(d) list, DWQ will present the use assessment methodology to the EMC at its January meeting. The methodology should reflect any changes made in response to public comment on the document. At that point, the EMC will determine if it wants changes.

Once the commission approves the methodology, DWQ will use it as a guide for its data collection and analysis over the following year. Ultimately, DWQ will propose the 2014 list of impaired waters, seeking public comment in March 2014.

Future 303(d) list cycles will follow the same process, except DWQ will issue the use assessment methodology for public comment in May of even-numbered years, with EMC consideration in September. In practice, that means each use assessment methodology comment period will immediately follow the April 1 EPA submission date of the previous 303(d) list.

Posted on November 29, 2012 by Erin Wynia