| Non-point source (NPS) pollution originates from diffuse sources in a watershed and contaminates the surface waters. Watershed characteristics such as land cover types, soil types, terrain features, and stream proximity strongly influence the kinds and amounts of NPS pollutant inputs to the surface waters. A Geographic Information System (GIS) is an appropriate tool for modeling these watershed attributes due to their geographic nature. This GIS model developed for the Onondaga Lake watershed compiles and analyzes some of these watershed attributes and calculates in-stream concentrations of three NPS pollution indicators at various points within the watershed. A comparison of sample data taken from the watershed tributaries is made with the results calculated by the GIS model and it is shown that reasonable estimates of in-stream concentrations of NPS pollutant indicators can be generated. The ability to reasonably calculate NPS pollutant loadings will become very useful. Ultimately, areas that yield high NPS loadings can be identified and appropriate water quality improvement projects can be implemented based on the characteristics of these areas. |
