Assessing fecal coliform fate and transport in a coastal watershed using HSPF

There is increasing concern regarding spread and proliferation of pathogenic microorganisms in watersheds and their impacts on water quality. In agricultural and rural watersheds fecal coliform occurrence, an indicator of pathogenic contamination, is often thought to be a result of land applications of animal waste. This study used the Hydrologic Simulation Program Fortran (HSPF) along with the Bacterial Indicator Tool to model fecal coliform transport in a coastal watershed with a view to identifying contaminant sources and key contributing areas. Results indicated that the highest levels of fecal coliform contamination (often exceeding the 400 counts/100 ml standard for the area) emanated from areas with and without livestock operations, and from largely forested areas, indicating that livestock operations were not the determining source of fecal coliform as suggested in previous studies. This study found HSPF to be an effective tool for identifying key coliform contributing areas in coastal watersheds.