Glossary of Stormwater Terms

Basin: the entire area of land drained by a river and its tributaries

Berm: A constructed barrier of compacted earth.

BMPs: Best Management Practices. Best available practices or devices that, when used singly or in combination, eliminate or reduce the contamination of surface and/or ground waters.

Catch basin: Curbside opening that collects rainwater from streets and serves as an entry point to the storm drain system.

Channel: A long narrow excavation or surface feature that conveys surface water and is open to the air.
Channel, natural: A channel which has occurred naturally due to the flow of surface waters.

Conveyance: The process of transporting or transmission of something from 1 place to another.

Culvert: Pipe or concrete box structure which drains open channels, swales, or ditches under a roadway or embankment typically with no catch basins or manholes along its length.

Ditch: a long narrow excavation dug in the earth for drainage of stormwater runoff.

Detention: Release of surface and storm water runoff from the site at a slower rate than it is collected by the drainage facility system, the difference being held in temporary storage.

Discharge: to cause or allow to throw, drain, release, dump, spill, empty, emit or pour any pollutants or harmful quantity of any substance into the municipal storm sewer system or into the waters of the United States.

Drainage: The collection, conveyance, containment, and/or discharge of surface and storm water runoff.

Erosion: When land is diminished or worn away due to wind, water, or glacial ice.

Flood: A temporary rise in flow or stage of any watercourse or stormwater conveyance system that results in stormwater runoff exceeding its normal flow boundaries and inundating adjacent, normally dry areas.

Floodplain: Areas adjacent to a stream or river that are subject to flooding or inundation during severe storm events (often called the 100-year floodplain, it would include the area or flooding that occurs, on average, once every 100 years). Sometimes referred to as the “FEMA Floodplain.

Grading: The cutting and/or filling of the land surface to a desired slope or elevation.

Groundwater: Underground water usually found in aquifers. Groundwater usually originates from infiltration. Runoff can seep into the soil and recharge groundwater that supplies drinking wells and springs.
Household Hazardous Waste: Your common, everyday products used in and around our homes. These include your average household cleaner, the oil in your car, and even the paint you use to spruce up your home. When disposed of improperly these everyday products can cause harm to humans, pets and the environment.

IDDE: Illicit Discharge Detection and Elimination.

Illicit Discharge: Any intentional discharge to the municipal storm sewer system that is not composed entirely of stormwater, except discharges pursuant to a permit, or discharges resulting from fire fighting activities.
Impervious surface: Any hard-surfaced area that prevents or retards the entry of water into the soil in the manner and to the extent that such water entered the soil under natural conditions, causing water to run off the surface in greater quantities or at an increased rate of flow than was present under natural conditions such as, but not limited to, roof tops, asphalt or concrete sidewalks, paving, driveways, parking lots, walkways, patio areas, storage areas, and gravel, bituminous substances or other surfaces which similarly affect the natural infiltration or runoff patterns of real property in its natural state.

Non-point Pollution Source: Caused by rainfall or snow melt mover over and through the ground. As the "run-off" moves it picks up natural and man-made pollutants and eventually deposits them into creeks and lakes. This is the largest source of storm water pollution.

Outfall: The point where wastewater or drainage discharges from a pipe, ditch, or other conveyance to a receiving body of water.

Point discharge: The release of collected and/or concentrated surface and storm water runoff from a pipe, culvert, or channel.

Pollutant: any dredge spoil, solid waste, incinerator residue, oil, grease, sewage, garbage, sewage sludge, munitions, medical waste, chemical waste, industrial waste, biological materials, radioactive materials, heat, wrecked or discarded equipment, rock, sand, cellar dirt, agricultural and industrial waste, and characteristics of the wastewater (i.e., pH, temperature, total suspended solids, turbidity, color, biochemical oxygen demand, chemical oxygen demand, toxicity, odor).

PUP: "Pick Up my Poop" reminder to please clean up after your pets. Pet waste can contribute to stormwater pollution.

Retention: The process of collecting and holding surface and storm water runoff with no surface outflow.

Riprap: A facing layer or protective mound of stones placed to prevent erosion or sloughing of a structure or embankment due to the flow of surface and storm water runoff.

Runoff: Water originating from rainfall and other precipitation that ultimately flows into drainage facilities, rivers, streams, springs, seeps, ponds, lakes, and wetlands as well as shallow groundwater.

SSO: Sanitary Sewer Overflow.

: Occurs when precipitation from rain or snow melt flows over the ground. Impervious surfaces like driveways, sidewalks, and streets prevent stormwater from naturally soaking into the ground.

Storm drain system: any facility, structure, improvement, development, equipment, property or interest therein, or other structural or nonstructural element made, constructed, used or acquired for the purpose of collecting, containing, storing, conveying and controlling stormwater wherever located including, but not limited to, storm sewers, curbs, street drains, conduits, natural and man-made channels, pipes, culverts and detention ponds whether public or private.

Storm drain: An opening leading to an underground pipe or open ditch for carrying surface runoff, separate from the sanitary sewer or wastewater system.

Stormwater Pollution: Debris, chemicals, dirt and other pollutants picked up by stormwater and carried to the storm sewer system and discharged into creeks and lakes. This water is untreated, therefore anything picked up along the way enters the waters we fish and swim in.

SWP3: Stormwater Pollution Prevention Plan. A document that describes all potential sources of pollution and the measures that will be taken to prevent pollution.