Glossary of stormwater terms
Best Management Practices (BMPs): The most effective and practical ways to control non-point sources of pollution from stormwater/urban runoff.
Catch Basins: Curbside opening that collects rainwater from streets and serves as an entry point to the storm drain system.
First Flush: The first big rain after an extended dry period, which flushes out the accumulated pollutants in the storm drain system.
Flood Control Channel: The open portion (often concrete-lined) of the storm drain system.
Gutter: The edge of a street (below the curb) designed to drain water runoff from streets, driveways and parking lots into catch basins.
Household Hazardous Waste: Common everyday products that people use in and around their homes including paint, paint thinner, herbicides, and pesticides that can be hazardous if not properly disposed of.
Illicit Connection: Any connection to the storm drain system that is not permitted; or any legitimate connection that is used for illegal discharge.
Illicit Discharge: Any discharge to the municipal separate storm sewer system that is not composed entirely of storm water, except for discharges allowed under an NPDES permit or waters used for firefighting operations.
MS4: A municipal separate storm sewer system is a conveyance or system of conveyances (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains.
Non-Point Source Pollution: Pollution that does not come from a single, identifiable source. Includes materials that wash from roofs, streets, yards, driveways, sidewalks and other land areas. Collectively, this is the largest source of stormwater pollution.
National Pollutant Discharge Elimination System (NPDES): The federal NPDES stormwater permitting program developed by the U.S. Environmental Protection Agency (EPA).
Outfall: A flow of water from one drainage system into a larger system, or into a body of water like a lake.
Point Source Pollution: Pollution from a single identifiable source such as a factory or a sewage-treatment plant. Most of this pollution is highly regulated at the state and local levels.
Pollution Prevention: The NPDES Permit defines this as including planning, schedules of activities, prohibition of practices, implementation of maintenance procedures and other management practices to prevent or reduce pollutants in stormwater/urban runoff discharges.
Source Control: Action to prevent pollution where it originates.
Storm Drain System: A vast network of underground pipes and open channels designed for flood control.
Stormwater: Water that is not absorbed into the ground. It runs over impervious surface picking up pollutant materials along the way and runs into storm drains and ultimately into waterways. Stormwater is not treated before it is discharged into waterways in Franklin and Grand Isle County.
Storm Water Pollution: Water from rain, irrigation, garden hoses or other activities that pick up pollutants (cigarette butts, trash, automotive fluids, used oil, paint, fertilizers and pesticides, lawn and garden clippings and pet waste) from streets, parking lots, driveways and yards and carries them through the storm drain system.
Watershed: A watershed is land that collects water and drains it into a river system or lake.