Stormwater Glossary

Catch basins: Curbside openings that collect rainwater from streets and serve as an entry point to the storm drain system.

Culverts: Pipe or concrete box structure that drains open channels or ditches under a roadway or embankment.

Daylighting: to take a stream out of a culvert and allow it to flow into its natural channel.

Erosion: The detachment and transport of soil or rock fragments by water, wind, ice, etc.

Illicit Connection: Discharge of pollutants or non-stormwater materials into storm sewer system via pipe or other connection.

Impervious: A surface through which stormwater is incapable of passing.

Runoff: Water from rain, melted snow, or landscaping irrigation that flows over land and into drainage facilities, local creeks, streams, and waterways. Runoff often carries pollutants in it.

Sanitary Sewer System: A system of sewers designed to collect and transport household and industrial wastewater from urban areas to a wastewater treatment plant.

Stormwater: Water that runs off surfaces such as rooftops, paved streets, highways, parking lots, gravel roads, and hard grassy surfaces like lawns and athletic fields. Water enters the storm drainage system and eventually empties into lakes, rivers, streams, and the ocean. Unmanaged or poorly managed stormwater can cause water quality problems, erosion, and flooding.

Stormwater Pollution: Water from rain, irrigation, garden hoses, or other activities that picks up pollutants, such as 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 and straight to waterways.

Stormwater Retention/Detention pond: A facility designed to retain stormwater runoff for a short period of time before releasing it to the stormwater conveyance system.

Stormwater System: The system built to collect and transport runoff to prevent street and property flooding. Components include drains, culverts, catch basins, and stormwater retention ponds. Anything that flows into the storm drainage system flows directly into local creeks, streams, and waterways. Stormwater runoff is not treated; the storm drainage system is completely separate from the sanitary sewer system.

Streambank: A bank slope.

Streambank Erosion: Removal of soil particles from a bank slope primarily due to water action. Changes in land use, climatic conditions, ice, debris, and chemical reactions can also cause stream bank erosion.

Streambank Stabilization and Restoration: The process of building and rebuilding the banks of streams, creeks, or rivers to prevent erosion and filter polluted runoff. Buffers can be planted to help restore a stream bank.

Watershed: An area of land that drains runoff to a particular stream, river, lake, or waterway.