A detention basin is designed to temporarily store stormwater runoff and then let it slowly drain out between rainfall events.
Naturalized detention basins are designed to provide greater water quality and habitat benefits relative to standard dry-bottom (usually turf) detention basins. They are stormwater control facilities that are planted with native vegetation in order to help improve stormwater quality. Naturalizing a detention basin with native vegetation eliminates the need for mowing. Immediately following the planting it is necessary to frequently inspect the basin to ensure the plants are establishing themselves properly. Planting native wildflowers will improve the detention basin’s aesthetic value. The vegetation can also provide habitat for wildlife, attracting birds and butterflies to the area. Trees, shrubs and grasses can all be used in a naturalized detention basin.
- Native vegetation helps filter out pollutants.
- Once established, native vegetation is low maintenance and provides wildlife habitat.
According to the US EPA, a wet detention pond is a stormwater control structure that provides both retention and treatment of contaminated stormwater runoff. It contains a perennial pool of water, which holds runoff from one rainfall event until displaced by a new rainfall event. This pool is the primary pollutant removal mechanism, such that solid particles drop out of suspension in the water column. In addition to this sedimentation, wet detention ponds also filter out pollutants via chemical processes and biological uptake. However, high flows from intense storms also temporarily reduce the pollutant removal capacity of wet basins.
- The amount of urban pollutants that a wet pond can filter depends on the ratio of the size of the detention pond to the runoff from the surrounding watershed.
- Typically, wet ponds are more effective at nutrient removal and stormwater quality control than dry basins.