Planning Level Evaluation of Densities and Sources of Indicator Bacteria in a Mixed Land Use Watershed

Abstract

The lower Buffalo River, NY, is environmentally impaired and the 38 combined sewer outfalls within this reach historically were believed to be the primary source of bacterial contamination. A planning level evaluation of bacteria contamination was done through sample testing and compilation of existing source data, in part, with the aid of GIS technology. The intent of such evaluation is to provide an overview of the magnitude and sources of the water quality problem without extensive resource commitments, as a first step in developing remediation strategies. Testing for fecal coliform and fecal streptococci was done at 12 sites within the watershed for one year, 1992–93. Indicator bacteria densities at all sites generally were high and the state guideline for primary contact (200 fecal coliform 100 ml−1) was exceeded in 69% of 277 samples. Bacteria densities were greatest during storm events, suggesting runoff as an important source pathway. Mean fecal coliform densities significantly increased downstrea...