Component: Channels & rills



Canals and rills are open surface water channels with hard edges. They are simply channels that water flows along whereby they can have a variety of cross sections to suit the urban landscape, including the use of planting to provide both enhanced visual appeal and water treatment.


Treatment channels collect water, slow it down and provide storage for silt and oil that is captured. The outlets are designed to act as a mini oil separator; hence the channels can be very effective at treating pollution.


Advantages & disadvantages



  • Effective in water & pollution treatment

  • Can act as pre-treatment to remove silt before water is conveyed into further SuDS features

  • Can be visually appealing in urban landscapes

  • Amenity value for the local community

  • Easy to construct

  • Good for biodiversity

  • Incorrect planting can cause silt build up

  • Need to give careful consideration to crossings








SuDS channels and rills






Where component can be used

Residential:  Yes

Commercial/industrial:  Yes

High density:  Yes

Retrofit:  Yes

Contaminated sites:  Yes (with liner)

Sites above vulnerable groundwater: Yes (with liner)



Peak flow reduction:  Medium

Volume reduction:  Medium

Water quality treatment: Medium – high (design dependent)

Amenity potential:  Medium – high (design dependent)

Ecology potential:  Design dependent



  • Routine maintenance

  • Removing litter/debris

  • Intensive maintenance required once every 5 years (i.e. to remove silt etc.)



Read more on:


SuDS Rill




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