Stormwater is generated by runoff from land and impervious areas such as paved streets, parking lots, and building rooftops during rainfall and snow events that often contain pollutants in quantities that could adversely affect water quality. Most stormwater discharges are considered point sources and require coverage by a National Pollutant Discharge Elimination System (NPDES) permit.
Point source pollution is generated from pollutants that enter a body of water directly from a specific source, usually a pipe. These are generally discharged as a result of agricultural, industrial or municipal activities.
Non-point source pollution is generated from a variety of sources. The pollutants are indirectly deposited. As runoff travels, it picks up and carries man-made and natural pollutants, transferring them into the various water sources. Non-point sources include the following:
- Animal wastes
- Hazardous wastes from landfills
- Herbicides, fertilizers, and insecticides
- Oil, grease, and chemical spills
- Sediments from construction sites
- Stream bank erosion
- Trash, litter, and other debris
The primary method to control stormwater discharges is through the use of best management practices (BMPs).
National Pollutant Discharge Elimination System (NPDES)
Water pollution degrades surface waters making them unsafe for drinking, fishing, swimming, and other activities. As authorized by the Clean Water Act, the National Pollutant Discharge Elimination System (NPDES) permit program controls water pollution by regulating point sources that discharge pollutants into waters of the United States.
Point sources are discrete conveyances such as pipes or man-made ditches. Individual homes that are connected to a municipal system, use a septic system, or do not have a surface discharge do not need an NPDES permit; however, industrial, municipal, and other facilities must obtain permits if their discharges go directly to surface waters. In most cases, the NPDES permit program is administered by authorized states like Georgia. Since its introduction in 1972, the NPDES permit program is responsible for significant improvements to our Nation's water quality.