Sustainable Drainage Systems (SuDS)
Conventional stormwater management has focused on quantity (flow) management, by collecting runoff and channeling it to the closest watercourse. This has had a significant impact on the environment through the erosion of natural channels, siltation of water bodies and pollution resulting environmental degradation.
SuDS offer an opportunity to protect and promote a healthy environment through designing for water quantity management; water quality treatment; enhanced amenity; and enhance biodiversity.
There are three key stages in the treatment train, each having slightly different combinations of SuDS options to control the stormwater:
i) Source Controls manage stormwater runoff as close to its source as possible, typically on site. Typical SuDS options include: green roofs, rainwater harvesting, permeable pavements and soakaways.
ii) Local Controls manage stormwater runoff in the local area, typically within the road reserves. Typical SuDS options include: bio-retention areas, filter strips, infiltration trenches, sand filters and swales.
iii) Regional Controls manage the combined stormwater runoff from several developments. Typical SuDS options include: constructed wetlands, detention ponds and retention ponds.
The South African Guidelines for Sustainable Drainage Systems