Retention Basin (Wet Pond)

Wet retention ponds are constructed basins that hold a permanent pool of water throughout the year, or at least during periods of normal rainfall. Pollutant removal occurs through settling, as stormwater runoff is stored in the pond and released slowly at a controlled rate. the release is is typically regulated by a combination of structures including risers, culverts, orifices and weirs.

The advantages of a wet pond over a dry pond are higher pollutant removal and less chance that pollutants will be re-suspended during a storm. Additional pollutant uptake of nutrients also occurs through biological activity (i.e. algal uptake). Wet ponds can also serve as an aesthetic or recreational amenity as well as a habitat for some wildlife. Wet ponds are among the most cost-effective and widely used BMP when space is available. However, wet ponds pose a higher safety liability than other SMFs. 



  • Conduct routine mowing

  • Keep embankments stable / fill animal burrows

  • Remove sediment from pond when necessary

  • Manage vegetation / seed and stabilize bare spots

  • Inspect and clean any mechanical components

  • Keep free of debris / remove trash

  • Keep risers, spillways and outlets clear

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