Component: Bioretention areas



Bioretention areas are shallow landscaped depressions which are typically under drained and rely on engineered soils, enhanced vegetation and filtration to remove pollution and reduce runoff downstream. They are aimed at managing and treating runoff from frequent rainfall events.


Advantages & disadvantages




  • Can be planned as landscaping features

  • Very effective in removing urban pollutants

  • Can reduce volume and rate of runoff

  • Flexible layout to fit into landscape

  • Well-suited for installation in highly impervious areas, provided the system is well-engineered and adequate space is made available

  • Good retrofit capability

  • Requires landscaping and management                                      

  • Susceptible to clogging if surrounding landscape is not managed

  • Not suitable for areas with steep slope





Where component can be used

SuDS bioretention area


Residential:  Yes

Commercial/industrial:  Yes

High density:  No

Retrofit:  Yes

Contaminated sites:  Yes

Sites above vulnerable groundwater: Yes



Peak flow reduction:  Medium

Volume reduction:  Medium (High with infiltration)

Water quality treatment: Good

Amenity potential:  Good

Ecology potential:  Medium



  • Regular inspection

  • Litter/debris removal

  • Replacement of mulch layer

  • Vegetation management

  • Soil spiking and scarifying



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