Sustainable Urban Drainage System (SuDS)
Sustainable Urban Drainage System (SuDS) is a Philosophy. It’s not just one type of component or a method, but a combination of various control measures at four key levels. Its aims is to mimic the natural drainage
SuDS is about
- Managing Water on the surface and,
- Treating water as close to the source as possible,
SuDS is not just about drainage. It’s about managing water quantity, water quality as well as providing biodiversity and amenity
SuDS Principles are also called as SuDS Management Train. Its about using a sequence of SuDS components to help manage the flow and volumes of water. In the process it also provides incremental improvements in water quality.
It normally starts with source control, moving to site control and regional control.
Source control means management of water as close to its source as possible. Its preferred in urbanised areas with high land cost. Generally, source control components are within the curtilage of properties and generally maintained by the property owner or the management.
Examples of Source Control
- Pavements and surfaces with materials that allow surface water to enter the underlying construction.
- Runoff is stored and conveyed through the sub-base construction.
- Provides attenuation, infiltration and some water treatment.
- Normally a multi layered system that covers a roof with vegetation over a drainage layer.
- This can reduce the volume of runoff and attenuate peak flows from the roof.
- Can reduce the size of other SuDS components
- Increases the aesthetics of the buildings
- Shallow channels designed to collect, convey and treat water.
- Generally two types of swales, normal and under drained swales
- Provide greater drainage, but often remain dry.
- Swale on the perimeter of the sites also provides opportunities to enhanced biodiversity.
Other Permeable surfaces
Site and Regional Control
Provides an opportunity to manage runoff in cost effective parcels at site level or at regional level, it also enables pollutants associated with different land uses to be managed more effectively.
Retention and detention
- These are designed to either provide storage, through the retention of surface water runoff, or attenuation through the detention of surface water runoff.
- Retention is primarily provided on the surface through ponds, and underground through tanks, commonly known as geocellular tanks.
- Detention is often provided by detention basins.
Examples of Site & Regional Control
- Attenuation tanks is a system, comprise of some sort of holding area (normally underground geocellular tanks) that fills up during a storm and releases water at a rate that the drains can handle without backing up.
- Retention ponds provide both storm water attenuation and treatment.
- Designed to support emergent and submerged aquatic vegetation along their shoreline.
- These are surface storage basins or facilities that provide flow control through attenuation of stormwater runoff. They also facilitate some settling of particulate pollutants.
- Detention basins are normally dry and in certain situations the land may also function as a recreational facility.
- This component is used towards the end of the SuDS management train
Benifits of SuDS
- Reduced flood risk
- Ground Water Recharge
- Improved water quality
- Increased biodiversity
- Increased levels of green infrastructure
- Better places to live
- Engagement with local communities
- Adaptation to climate change
- Carbon management
- Learning opportunities – School, College & Universities