Stormwater runoff is a leading source of water pollution. Stormwater runoff can harm surface waters such as rivers, lakes, and streams - which in turn cause or contribute to water quality standards being exceeded.
Common pollutants include oil and grease from roadways, pesticides and fertilizers from lawns, sediment from construction sites, and carelessly discarded trash, such as cigarette butts, paper wrappers, and plastic bottles. When the untreated storm water is deposited into nearby waterways through municipal separate storm sewer system (MS4) discharges, these pollutants can impair the waterways, thereby discouraging recreational use of the resource, contaminating drinking water supplies, and interfering with the habitat for fish, other aquatic organisms, and wildlife.
Stormwater runoff can change natural hydrologic patterns, accelerate stream flows, destroy aquatic habitats, and elevate pollutant concentrations and loadings. Development substantially increases runoff from city streets, driveways, parking lots, and sidewalks, on which pollutants from human activities settle.
Stormwater runoff within the City of Greenville flows through a municipal separate storm sewer system (MS4) and ultimately discharges into local rivers and streams, not the wastewater treatment plant. The US Environmental Protection Agency (EPA) regulates these stormwater discharges through the National Pollutant Discharge Elimination System (NPDES) stormwater Program. This program requires that the City of Greenville implement an MS4 stormwater management program with the intent to improve the Nation's waterways by reducing the pollutants that stormwater runoff picks up and carries into the stormwater systems during storm events.
Through the MS4 general permit, the City of Greenville is required to develop a stormwater management plan that incorporates best management practices (BMPs) applicable to our MS4. There are six program components, known as minimum control measures (MCMs), that must be implemented. They are: