What are sustainable drainage systems (SUDS)?
What are sustainable drainage systems (SUDS)?
Sustainable drainage systems (SUDS) provide a natural approach to managing drainage in and around developments.
SUDS work by slowing and holding back the run-off from a site, allowing natural processes to break down pollutants. SUDS deal with run-off close to the source, rather than transporting it elsewhere.
Benefits of sustainable drainage systems (SUDS)
Prevent diffuse water pollution from built up areas.
Slow down surface water run-off from your site to help reduce the chances of flooding.
Reduce the risk of sewer flooding during heavy rain.
Recharge groundwater to help prevent drought.
Provide valuable habitats for wildlife in built up areas.
Create green spaces for people in urban areas.
SUDS techniques
You could use the following SUDS techniques on your site:
green roofs
permeable surfaces
infiltration trenches
filter drains and filter strips
swales (shallow drainage channels)
detention basins
purpose built ponds and wetlands.
Treating run-off
You can use SUDS to treat lightly polluted run-off from your site, and reduce your impact on the environment.
Source control methods allow you to manage run-off at, or close to, the surface where rainfall lands. You can use all the SUDS techniques listed above for sites such as:
roofs
yards
car parks
farmsteads
minor roads.
You can use SUDS to manage the surface water run-off from larger areas, such as part of a housing estate, major roads or business parks. This is known as site control.
Source control measures alone may control the run-off from your site from showers or light rain. Persistent rain or heavy downpours will produce more runoff. Site control measures can prevent this from discharging directly to the water environment. You can channel run-off from larger areas to a site control measure using swales or filter drains.
Downstream of source controls and site controls you can install regional control measures, for the gathered run-off from a large area. These systems involve the same principles as the smaller scale SUDS but can cope with larger volumes of water.
The rainwater that passes through small SUDS can feed into larger SUDS which deal with the gathered run-off from a wide area. Where possible the flows between SUDS components should not involve pipes. You should connect SUDS measures with swales, filter drains or ditches.
You must not use SUDS to treat sewage, heavily contaminated run-off or trade effluent.
If you pollute the water environment, you are probably committing an offence.