ABSTRACT
Surface and groundwater polluting discharges originate from two source types and are classified as: (1) identifiable point sources, and (2) nonpoint sources (NPS). The latter source produces diffused wastes into waters by land runoff, washout from the atmosphere, or other means. Examples of point sources for polluting waters are municipal sewer systems, storm water runoff, industrial wastes, and animal wastes from commercial feedlots. Examples of NPS are natural drainage sediments, agricultural chemicals, mine drainage, and spills of hazardous substances. NPS pollution does not result from a discharge at a single, specific location, but results from land runoff, precipitation, snowmelt, atmospheric deposition, drainage, or seepage.
