Cooperation in Implementation: Setting Goals Using NPDES Phase II

South Carolina is one of the few states not currently under Consent Decree to complete TMDLs. However, the South Carolina Department of Health and Environmental Control (SCDHEC) recently finished development of a nonpoint source TMDL for Dorchester Creek and Sawmill Branch Canal in coastal South Carolina near Summerville, SC. The TMDL was developed by SCDHEC as a result of the creek and canal being listed on the 303(d) list for fecal coliform.Dorchester Creek and Sawmill Branch had previously been channelized (Figure 1) as part of a U.S. Army Corps of Engineers (USACE) drainage project. Of major concern to watershed stakeholders was the assessment of the canal based on an instantaneous maximum of 400 colony-forming units per milliliter (cfu/ml). Application of such a standard would be extremely difficult to achieve in such a man-made system designed for drainage, not for its designated uses of primary contact such as swimming or recreational contact such as boating.The main concern of stakeholders was the draft TMDL's stated need for a 96 percent reduction in fecal coliform loads in the canal and creek. A lack of extensive fecal coliform monitoring in the area made proper source identification and subsequent allocations impossible. A variety of source_, such as septic tank failures, compromised sewer lines, wildlife, and illicit dischargers were indicated in the TMDL as being major contributors to fecal levels, but the basis of such claims was questionable. Due to the uncertainty of the source of the fecal coliform and the basis of the TMDL, stakeholders (Dorchester County, South Carolina and the Town of Summerville) challenged the validity and accuracy of the draft TMDL. After extensive review of the draft TMDL, the stakeholders provided formal written comments and conducted informal meetings with SCDHEC to resolve the two main issues set forth in the draft TMDL: specific limits for each nonpoint source entering the canal system and inclusion of an implementation plan.As this process was in progress, SCDHEC's NPDES Phase II Stormwater Program in South Carolina was being implemented as well. Due to SCDHEC's decision to issue individual NPDES Phase II permits for affected communities in lieu of general permits, the draft TMDL threatened to place numeric effluent limits on affected communities through the Phase II stormwater program. Through the NPDES Phase II Stormwater permitting process, Dorchester County and the Town of Summerville had already developed a Stormwater Quality Management Program that spans the duration of the 5- year renewable permit and includes a comprehensive NPS management planning process. Components of this program already included the detection and elimination of illicit discharges, thereby improving stream water quality.Using a recent memo from EPA as a guide, SCDHEC, Dorchester County, and the Town of Summerville were able to modify the goals of the TMDL by using individual permit conditions already developed under Phase II MS4 regulations. These conditions were considered the means to reach the goals of the TMDL in lieu of specific numeric limits for NPS discharges. Based on the EPA memo, the stakeholders were able to change the draft TMDL so that effluent limits are expressed as best management practices (BMPs) or other similar requirement instead of as numeric effluent limits.This paper reviews the process used by SCDHEC and the affected municipalities to develop this cooperative and proactive effort to address reductions in fecal coliform loading in the Dorchester Creek and Sawmill Branch watersheds without inclusion of complex and non-obtainable numeric limits. The collective experience in the process provides an excellent example of how regulatory agencies, municipalities, and stakeholders can work together when faced with the issue of implementing nonpoint source TMDLs.