Component: Rain gardens

 

Description 

Rain gardens are relatively small depressions in the ground that can act as infiltration points for roof water and other ‘clean’ surface water – i.e. water that is low in contamination levels.

 

Rain gardens are most likely to be implemented on private property close to buildings. In order for roof water to reach a rain garden, property downpipes are often disconnected from the drainage system and redirected.

 

Rain gardens should be planted up with native vegetation that is happy with occasional inundations.

 

Advantages & disadvantages

Advantages	Disadvantages
Easy to retrofit Small, so minimal land take Attractive features that can help to improve open space                  Can be planned as landscaping features Can reduce rate of run off and some volume reduction Flexible layout to fit into landscape Can be installed in impervious areas if designed correctly Easy to maintain	As they are often small, their impact on volume reduction can be limited Requires landscaping and management Susceptible to clogging if surrounding landscape is not managed Not suitable for areas with steep slopes

 

 

 

 

 

Where component can be used 

Residential:  Yes

Commercial/industrial:  Yes

High density:  Yes

Retrofit:  Yes

Contaminated sites:  No

Sites above vulnerable groundwater: No

 

Performance 

Peak flow reduction:  Good

Volume reduction:  Medium

Water quality treatment: Medium

Amenity potential:  Good

Ecology potential:  Good

 

Maintenance 

• Litter/trash removal

• Inlet/outlet cleaning

• Vegetation management

 

 

Read more on:

• SuDS components

• Soakaways

• Infiltration trenches

• Infiltration basins

• Infiltration overview