Fecal Coliform Total Maximum Daily Load for the Upper North Buffalo Creek Watershed City of Greensboro, Guilford County

The City of Greensboro's Department of Water Resources, in partnership with the NC Division of Water Quality (DWQ) and local stakeholders, have developed a fecal coliform Total Maximum Daily Load (TMDL) for the upper North Buffalo Creek watershed, approved by EPA in April, 2004. The TMDL is designed to provide an objective analysis of potential sources of bacteriological contamination within the watershed, as well as the predicted impact these sources have on water quality under a variety of weather and stream flow conditions. The overall management goal is to reduce instream fecal coliform concentrations to meet NC Water Quality Standards as well as a level such that recreational users can safely enjoy clean streams throughout the watershed.In an effort to implement strategies to achieve the goals established in the TMDL, the City of Greensboro has completed a Water Quality Investigation of North Buffalo Creek to identify dry weather sources of bacterial contamination in the TMDL watershed. This study is supported by aerial infrared imagery taken in March 2003 to aid in the detection of illicit discharges from the stormwater conveyance system and other sources. Overlaying the locations of thermal anomalies from the aerial infrared imagery on the stormwater inventory database in a GIS format proved to be an effective tool for locating potential sources of bacterial contamination. As a direct result of this study, the City of Greensboro has located three specific sources of bacterial contamination from sanitary sewers and illicit discharges to the stormwater conveyance system. In addition to reducing the sources of contamination identified in the Water Quality Investigation, the City of Greensboro is also undergoing a 45 million sanitary sewer replacement in the North Buffalo Creek watershed. These measures will provide a starting point for meeting the dry weather water quality target identified in the TMDL. North Buffalo Creek is one of several streams being investigated as part of a Microbial Source Tracking (MST) study managed by DWQ and supported by the City of Greensboro. The study will help provide additional insight to the sources of fecal coliform in the watershed especially during wet weather conditions. Additional implementation measures will be identified in the North Buffalo Creek master plan, which is part of a citywide endeavor to study each of the watersheds in the City limits.The specific implementation strategies outlined above are intended to help meet the two water quality targets defined in the TMDL. Providing a dry weather and wet weather water quality target allows local watershed managers to focus on reducing pollutant loads during a period when user exposure to potential pathogens is more likely while at the same time reflecting a longer term goal for achieving standards when the number of potential contributing sources is high. To identify of potential sources of fecal coliform loads within the watershed a detailed source assessment was performed as part of the TMDL development process. With stakeholder input, an effort was made to explicitly identify as many source types as was practical. Sources included contributions from the municipal separate stormwater system (MS4) and various nonpoint stormwater sources. To assess the load contributions from the various sources to the TMDL compliance point (Summit Avenue), a calibrated WinHSPF model was created by incorporating local precipitation and water quality monitoring data.