Sustainable Drainage Systems (SUDS) is an approach to drainage which seeks to decrease the amount of surface runoff, decrease the velocity of surface runoff, or divert it for other useful purposes, thereby reducing the contribution it makes to sewer discharge and flooding.

As well as controlling the quantity of runoff, SUDS can also improve the quality of runoff, preventing pollutants from entering the drainage system. SUDS will also ‘green’ the urban environment and should provide landscape, amenity and biodiversity benefits too.

Techniques that come under the SUDS umbrella vary enormously but usually involve some of the following components:

• Permeable and porous surfaces to reduce surface runoff
• Ponds/basins for temporary storage during high magnitude rainfall events (detention basins) or longer term storage (retention basins)
• Pipework and channeling to divert water from undesirable locations
• Structures that increase the lag between a rainfall event and discharge of water to the drainage system by increasing infiltration. ⁽¹⁾

The SUDS approach is particularly valuable in urban areas where high density development and impermeable surfaces mean surface runoff can easily cause flooding, either directly or indirectly through sewer flooding.

Work by Scotland and Northern Ireland Forum for Environmental Research has shown that of the 767 SUDS sites in Scotland recorded in late 2001, most were part of residential and commercial/retail developments (48.6% and 22.4% respectively) as well as industrial and roadside developments ⁽²⁾.

Case Studies

The following organisations have some interesting case studies of SUDS projects in the UK:

CIRIA (Construction Industry Research and Information Association) http://www.ciria.org.uk/suds/case_studies.htm

UK SUDS Database http://www.suds-sites.net/default.asp

References

(1) CIRIA http://www.ciria.org.uk/suds/

(2) Wild, T.C, Jefferies, C, D’Arcy, B.J. (2002) SUDS in Scotland – the Scottish SUDS database. SNIFFER. http://www.sniffer.org.uk

(3) Sustainable Drainage Systems (SUDS): an introduction. (2003) Environment Agency.

(4) Sustainable Urban Drainage Systems Network http://sudsnet.abertay.ac.uk/index.html

(5) Environment and Heritage Service (Northern Ireland) http://www.ehsni.gov.uk/

(6) Scottish Environment Protection Agency http://www.sepa.org.uk/dpi/suds/index.htm

(7) Guidance to proprietary sustainable drainage systems and components. (2005) British Water. http://www.britishwater.co.uk/Tech_Guidance_SUDS-final-1Jun05.pdf