Component: Wetlands


Wetlands provide both stormwater attenuation and treatment. They comprise shallow ponds and marshy areas, covered almost entirely in aquatic vegetation. Wetlands detain flows for an extended period to allow sediments to settle, and to remove contaminates by facilitating adhesion to vegetation and aerobic decomposition. They also provide significant ecological benefits.


Advantages and disadvantages




  • Good removal capability or urban pollutants

  • If lined, can be used where groundwater is vulnerable

  • Good community acceptability

  • High potential ecological, aesthetic and amenity benefits

  • May add value to local property. 

  • Land take is high

  • Requires baseflow

  • Limited depth range for flow attenuation

  • May release nutrients during non-growing season

  • Little reduction in run volume

  • Not suitable for steep sites

  • Colonisation by invasive species would increase maintenance

  • Performance vulnerable to high sediment inflows.



Where component can be used 

Residential: Yes

Commercial/industrial: Yes

High density: Unlikely

Retrofit: Unlikely

Contaminated sites: Yes (with liner)

Sites above vulnerable groundwater: Yes (with liner)




Peak flow reduction: Good

Volume reduction: Poor

Water quality treatment: Good

Amenity potential: Good

Ecology potential: Good




  • Litter/trash/debris removal

  • Inlet/outlet cleaning

  • Vegetation management to retain high vegetation coverage, possibly requiring specialist equipment

  • Sediment monitoring and removal when required.


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SuDS Component Wetlands

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