Sustainable drainage system


Sustainable drainage systems (also known as SuDS,[1] SUDS,[2][3] or sustainable urban drainage systems[4]) are a collection of water management practices that aim to align modern drainage systems with natural water processes and are part of a larger green infrastructure strategy.[5] SuDS efforts make urban drainage systems more compatible with components of the natural water cycle such as storm surge overflows, soil percolation, and bio-filtration. These efforts hope to mitigate the effect human development has had or may have on the natural water cycle, particularly surface runoff and water pollution trends.[6]

Retention ponds such as this one in Dunfermline, Scotland are considered components of a sustainable drainage system.

SuDS have become popular in recent decades as our understanding of how urban development affects natural environments, as well as concern for climate change and sustainability, have increased. SuDS often use built components that mimic natural features in order to integrate urban drainage systems into the natural drainage systems or a site as efficiently and quickly as possible. SUDS infrastructure has become a large part of the Blue-Green Cities demonstration project in Newcastle-upon-Tyne.[7]

History of drainage systemsEdit

Drainage systems have been found in ancient cities over 5,000 years old, including Minoan, Indus, Persian, and Mesopotamian civilizations.[8] These drainage systems focused mostly on reducing nuisances from localized flooding and waste water. Rudimentary systems made from brick or stone channels constituted the extent of urban drainage technologies for centuries. Cities in Ancient Rome also employed drainage systems to protect low-lying areas from excess rainfall. When builders began constructing aqueducts to import fresh water into cities, urban drainage systems became integrated into water supply infrastructure for the first time as a unified urban water cycle.[9]

London Sewage system being built in 1860

Modern drainage systems did not appear until the 19th century in Western Europe, although most of these systems were primarily built to deal with sewage issues rising from rapid urbanization. One such example is that of the London sewerage system, which was constructed to combat massive contamination of the River Thames. At the time, the River Thames was the primary component of London's drainage system, with human waste concentrating in the waters adjacent to the densely populated urban center. As a result, several epidemics plagued London's residents and even members of Parliament, including events known as the 1854 Broad Street cholera outbreak and the Great Stink of 1858.[10] The concern for public health and quality of life launched several initiatives, which ultimately led to the creation of London's modern sewerage system designed by Joseph Bazalgette.[11] This new system explicitly aimed to ensure waste water was redirected as far away from water supply sources as possible in order to reduce the threat of waterborne pathogens. Since then, most urban drainage systems have aimed for similar goals of preventing public health crises.

Within past decades, as climate change and urban flooding have become increasingly urgent challenges, drainage systems designed specifically for environmental sustainability have become more popular in both academia and practice. The first sustainable drainage system to utilize a full management train including source control in the UK was the Oxford services motorway station designed by SuDS specialists Robert Bray Associates[12] Originally the term SUDS described the UK approach to sustainable urban drainage systems. These developments may not necessarily be in "urban" areas, and thus the "urban" part of SuDS is now usually dropped to reduce confusion. Other countries have similar approaches in place using a different terminology such as best management practice (BMP) and low-impact development in the United States,[13] water-sensitive urban design (WSUD) in Australia,[14] low impact urban design and development (LIUDD) in New Zealand,[15] and comprehensive urban river basin management in Japan.[14]


Traditional urban drainage systems are limited by various factors including volume capacity, damage or blockage from debris and contamination of drinking water. Many of these issues are addressed by SuDS systems by bypassing traditional drainage systems altogether and returning rainwater to natural water sources or streams as soon as possible. Increasing urbanisation has caused problems with increased flash flooding after sudden rain. As areas of vegetation are replaced by concrete, asphalt, or roofed structures, leading to impervious surfaces, the area loses its ability to absorb rainwater. This rain is instead directed into surface water drainage systems, often overloading them and causing floods.

The goal of all sustainable drainage systems is to use rainfall to recharge the water sources of a given site. These water sources are often underlying the water table, nearby streams, lakes, or other similar freshwater sources. For example, if a site is above an unconsolidated aquifer, then SuDS will aim to direct all rain that falls on the surface layer into the underground aquifer as quickly as possible. To accomplish this, SuDS use various forms of permeable layers to ensure the water is not captured or redirected to another location. Often these layers include soil and vegetation, though they can also be artificial materials.

The paradigm of SuDS solutions should be that of a system that is easy to manage, requiring little or no energy input (except from environmental sources such as sunlight, etc.), resilient to use, and being environmentally as well as aesthetically attractive. Examples of this type of system are basins (shallow landscape depressions that are dry most of the time when it's not raining), rain gardens (shallow landscape depressions with shrub or herbaceous planting), swales (shallow normally-dry, wide-based ditches), filter drains (gravel filled trench drain), bioretention basins (shallow depressions with gravel and/or sand filtration layers beneath the growing medium), reed beds and other wetland habitats that collect, store, and filter dirty water along with providing a habitat for wildlife.

A common misconception of SuDS is that they reduce flooding on the development site. In fact the SuDS is designed to reduce the impact that the surface water drainage system of one site has on other sites. For instance, sewer flooding is a problem in many places. Paving or building over land can result in flash flooding. This happens when flows entering a sewer exceed its capacity and it overflows. The SuDS system aims to minimise or eliminate discharges from the site, thus reducing the impact, the idea being that if all development sites incorporated SuDS then urban sewer flooding would be less of a problem. Unlike traditional urban stormwater drainage systems, SuDS can also help to protect and enhance ground water quality.

Example featuresEdit

Because SuDS describe a collection of systems with similar components or goals, there is a large crossover between SuDS and other terminologies dealing with sustainable urban development.[16] The following are examples generally accepted as components in a SuDS system:

Roadside bioswale designed to filter storm water runoff from street surfaces


Two bioswales for a housing development. The foreground one is under construction while the background one is established.

Bioswales are channels designed to concentrate and convey stormwater runoff while removing debris and pollution. Bioswales can also be beneficial in recharging groundwater.

Bioswales are typically vegetated, mulched, or xeriscaped.[17] They consist of a swaled drainage course with gently sloped sides (less than 6%).[18]: 19  Bioswale design is intended to safely maximize the time water spends in the swale, which aids the collection and removal of pollutants, silt and debris. Depending on the site topography, the bioswale channel may be straight or meander. Check dams are also commonly added along the bioswale to increase stormwater infiltration. A bioswale's make-up can be influenced by many different variables, including climate, rainfall patterns, site size, budget, and vegetation suitability.

It is important to maintain bioswales to ensure the best possible efficiency and effectiveness in removal of pollutants from stormwater runoff. Planning for maintenance is an important step, which can include the introduction of filters or large rocks to prevent clogging. Annual maintenance through soil testing, visual inspection, and mechanical testing is also crucial to the health of a bioswale.

Bioswales are commonly applied along streets and around parking lots, where substantial automotive pollution settles on the pavement and is flushed by the first instance of rain, known as the first flush. Bioswales, or other types of biofilters, can be created around the edges of parking lots to capture and treat stormwater runoff before releasing it to the watershed or storm sewer.

Permeable pavement

Permeable paving demonstration

Permeable paving surfaces are made of either a porous material that enables stormwater to flow through it or nonporous blocks spaced so that water can flow between the gaps. Permeable paving can also include a variety of surfacing techniques for roads, parking lots, and pedestrian walkways. Permeable pavement surfaces may be composed of; pervious concrete, porous asphalt, paving stones, or interlocking pavers.[19] Unlike traditional impervious paving materials such as concrete and asphalt, permeable paving systems allow stormwater to percolate and infiltrate through the pavement and into the aggregate layers and/or soil below. In addition to reducing surface runoff, permeable paving systems can trap suspended solids, thereby filtering pollutants from stormwater.[20]

Permeable pavement is commonly used on roads, paths and parking lots subject to light vehicular traffic, such as cycle-paths, service or emergency access lanes, road and airport shoulders, and residential sidewalks and driveways.


Artificial wetlands can be constructed in areas that see large volumes of storm water surges or runoff. Built to replicate shallow marshes, wetlands as BMPs gather and filter water at scales larger than bioswales or rain gardens. Unlike bioswales, artificial wetlands are designed to replicate natural wetlands processes as opposed to having an engineered mechanism within the artificial wetland. Because of this, the ecology of the wetland (soil components, water, vegetation, microbes, sunlight processes, etc.) becomes the primary system to remove pollutants.[21] Water in an artificial wetland tends to be filtered slowly in comparison to systems with mechanized or explicitly engineered components.

Wetlands can be used to concentrate large volumes of runoff from urban areas and neighborhoods. In 2012, the South Los Angeles Wetlands Park was constructed in a densely populated inner-city district as a renovation for a former LA Metro bus yard. The park is designed to capture runoff from surrounding surfaces as well as storm water overflow from the city's current drainage system.[22]

Trounce Pond in Saskatoon, Canada serves as a storm water detention basin within the local drainage system.

Detention basins

Trounce Pond, a retention basin landscaped with natural grassland plants, in Saskatoon, Saskatchewan, Canada
The Corporate Park retention basin in Stafford, Texas, United States
Retention basin in Pinnau, Schleswig-Holstein, Germany

A retention basin, sometimes called a wet pond, wet detention basin, or stormwater management pond (SWMP), is an artificial pond with vegetation around the perimeter, and includes a permanent pool of water in its design.[23][24][25] It is used to manage stormwater runoff, for protection against flooding, for erosion control, and to improve water quality in an adjacent bodies of water.

It is distinguished from a detention basin, sometimes called a "dry pond", which temporarily stores water after a storm, but eventually empties out at a controlled rate to a downstream water body. It also differs from an infiltration basin which is designed to direct stormwater to groundwater through permeable soils.

Wet ponds are frequently used for water quality improvement, groundwater recharge, flood protection, aesthetic improvement, or any combination of these. Sometimes they act as a replacement for the natural absorption of a forest or other natural process that was lost when an area is developed. As such, these structures are designed to blend into neighborhoods and viewed as an amenity.[26]

In urban areas, impervious surfaces (roofs, roads) reduce the time spent by rainfall before entering into the stormwater drainage system. If left unchecked, this will cause widespread flooding downstream. The function of a stormwater pond is to contain this surge and release it slowly. This slow release mitigates the size and intensity of storm-induced flooding on downstream receiving waters. Stormwater ponds also collect suspended sediments, which are often found in high concentrations in stormwater water due to upstream construction and sand applications to roadways.

Green roofs

Green roof at the British Horse Society headquarters
Green roof of Chicago City Hall

A green roof or living roof is a roof of a building that is partially or completely covered with vegetation and a growing medium, planted over a waterproofing membrane. It may also include additional layers such as a root barrier and drainage and irrigation systems.[27] Container gardens on roofs, where plants are maintained in pots, are not generally considered to be true green roofs, although this is debated. Rooftop ponds are another form of green roofs which are used to treat greywater.[28] Vegetation, soil, drainage layer, roof barrier and irrigation system constitute green roof.[29]

Green roofs serve several purposes for a building, such as absorbing rainwater, providing insulation, creating a habitat for wildlife, increasing benevolence[30] and decreasing stress of the people around the roof by providing a more aesthetically pleasing landscape, and helping to lower urban air temperatures and mitigate the heat island effect.[31] Green roofs are suitable for retrofit or redevelopment projects as well as new buildings and can be installed on small garages or larger industrial, commercial and municipal buildings.[27] They effectively use the natural functions of plants to filter water and treat air in urban and suburban landscapes.[32] There are two types of green roof: intensive roofs, which are thicker, with a minimum depth of 12.8 cm (5+116 in), and can support a wider variety of plants but are heavier and require more maintenance, and extensive roofs, which are shallow, ranging in depth from 2 cm (1316 in) to 12.7 cm (5 in), lighter than intensive green roofs, and require minimal maintenance.[33]

The term green roof may also be used to indicate roofs that use some form of green technology, such as a cool roof, a roof with solar thermal collectors or photovoltaic panels. Green roofs are also referred to as eco-roofs, oikosteges, vegetated roofs, living roofs, greenroofs and VCPH[34] (Horizontal Vegetated Complex Partitions)

See alsoEdit


  1. ^ Sustainable Drainage System (SuDs) for Stormwater Management: A Technological and Policy Intervention to Combat Diffuse Pollution, Sharma, D., 2008
  2. ^ "CIRIA guide to SUDS". Retrieved 2014-01-21.
  3. ^ Scottish Government. Planning Services (2001). "Planning and Sustainable Urban Drainage Systems." Planning Advice Note 61. 2001-07-27.
  4. ^ "Sustainable Urban Drainage Systems". Retrieved 2020-11-15.
  5. ^ CIRIA SuDS Manual (Document reference : CIRIA C753), 2015
  6. ^ Hoang, L (2016). "System interactions of stormwater management using sustainable urban drainage systems and green infrastructure". Urban Water Journal. 13 (7): 739–758. doi:10.1080/1573062X.2015.1036083.
  7. ^ O’Donnell, E. C.; Lamond, J. E.; Thorne, C. R. (2017). "Recognising barriers to implementation of Blue-Green Infrastructure: a Newcastle case study". Urban Water Journal. 14 (9): 964–971. doi:10.1080/1573062X.2017.1279190. ISSN 1573-062X.
  8. ^ Angelakis, Andreas; De Feo, Giovanni; Laureano, Pietro; Zourou, Anastasia (2013-07-08). "Minoan and Etruscan Hydro-Technologies". Water. 5 (3): 972–987. doi:10.3390/w5030972. ISSN 2073-4441.
  9. ^ Burian Steven J.; Edwards Findlay G. (2002). "Historical Perspectives of Urban Drainage". Global Solutions for Urban Drainage. Proceedings: 1–16. doi:10.1061/40644(2002)284. ISBN 978-0-7844-0644-1.
  10. ^ "Re-Smelling London's Great Stink Of 1858". All That's Interesting. 2017-12-07. Retrieved 2019-04-21.
  11. ^ "BBC - History - Joseph Bazalgette". Retrieved 2019-04-21.
  12. ^ CIRIA Oxford Motorway Services Case Study
  13. ^ "Reducing Stormwater Costs through Low Impact Development Strategies and Practices". Fact Sheet. Washington, D.C.: U.S. Environmental Protection Agency (EPA). December 2007. EPA 841/F-07/006A.
  14. ^ a b Chen, Chi-Feng; Sheng, Ming-Yang; Chang, Chia-Ling; Kang, Shyh-Fang; Lin, Jen-Yang (2014). "Application of the SUSTAIN Model to a Watershed-Scale Case for Water Quality Management". Water. 6 (12): 3575–3589. doi:10.3390/w6123575. ISSN 2073-4441.
  15. ^ Eckart, Kyle; McPhee, Zach; Bolisetti, Tirupati (2017). "Performance and implementation of low impact development – A review". Science of the Total Environment. 607–608: 413–432. Bibcode:2017ScTEn.607..413E. doi:10.1016/j.scitotenv.2017.06.254. PMID 28704668.
  16. ^ Campos, Priscila Celebrini de Oliveira; Paz, Tainá da Silva Rocha; Lenz, Letícia; Qiu, Yangzi; Alves, Camila Nascimento; Simoni, Ana Paula Roem; Amorim, José Carlos Cesar; Lima, Gilson Brito Alves; Rangel, Maysa Pontes; Paz, Igor (2020). "Multi-Criteria Decision Method for Sustainable Watercourse Management in Urban Areas". Sustainability. 12 (16): 6493. doi:10.3390/su12166493.
  17. ^ "Stormwater Best Management Practice: Grassed Swales" (PDF). Washington, D.C.: U.S. Environmental Protection Agency (EPA). December 2021. p. 3. EPA 832-F-21-031P.
  18. ^ Loechl, Paul M.; et al. (2003). Design Schematics for a Sustainable Parking Lot (PDF). Champaign, IL: US Army Corps of Engineers, Research and Development Center. Archived from the original (PDF) on 2010-06-02. Construction Engineering Research Laboratory. Document no. ERDC/CERL TR-03-12.
  19. ^ US EPA, OW (2015-09-30). "What is Green Infrastructure?". US EPA. Retrieved 2019-08-16.
  20. ^ Interlocking Concrete Pavement Institute,
  21. ^ Constructed wetlands. Kandasamy, Jaya., Vigneswaran, Saravanamuthu, 1952-. New York: Nova Science Publishers. 2008. ISBN 9781616680817. OCLC 847617134.{{cite book}}: CS1 maint: others (link)
  22. ^ Fuentes, Ed (2012-02-14). "Innovative Wetlands Park Opens in South Los Angeles". KCET. Retrieved 2019-04-21.
  23. ^ Water Environment Federation, Alexandria, VA; and American Society of Civil Engineers, Reston, VA. "Urban Runoff Quality Management." WEF Manual of Practice No. 23; ASCE Manual and Report on Engineering Practice No. 87. 1998. ISBN 1-57278-039-8. Chapter 5.
  24. ^ U.S. Environmental Protection Agency. Washington, D.C. "Preliminary Data Summary of Urban Storm Water Best Management Practices." Chapter 5. August 1999. Document No. EPA-821-R-99-012.
  25. ^ University of Florida Institute of Food and Agricultural Sciences. "If you build it they will come: Frogs flourish in humanmade ponds." ScienceDaily. ScienceDaily, 27 August 2015. <>.
  26. ^ Mississippi State University. College of Engineering. Stormwater Retention Basins. Chapter 4, Best Management Practices.
  27. ^ a b Rodriguez Droguett, Barbara (2011). Sustainability assessment of green infrastructure practices for stormwater management: A comparative emergy analysis (Thesis). ProQuest 900864997.
  28. ^ Özyavuz, Murat, B. Karakaya, and D. G. Ertin. "The Effects of Green Roofs on Urban Ecosystems." GreenAge Symposium 2015.
  29. ^ EPA (2017) Green Roofs. U.S. EPA. Available from:
  30. ^ "Benefits of Green Roofs". Archived from the original on 4 July 2018. Retrieved 1 November 2018.
  31. ^ Vandermeulen, Valerie; Verspecht, Ann; Vermeire, Bert; Van Huylenbroeck, Guido; Gellynck, Xavier (November 2011). "The use of economic valuation to create public support for green infrastructure investments in urban areas". Landscape and Urban Planning. 103 (2): 198–206. doi:10.1016/j.landurbplan.2011.07.010.
  32. ^ "System Overview : Planted Roof : GSA Sustainable Facilities Tool".
  33. ^ Volder, Astrid; Dvorak, Bruce (February 2014). "Event size, substrate water content and vegetation affect storm water retention efficiency of an un-irrigated extensive green roof system in Central Texas". Sustainable Cities and Society. 10: 59–64. doi:10.1016/j.scs.2013.05.005.
  34. ^ "Archived copy". Archived from the original on 24 August 2011. Retrieved 19 May 2011.{{cite web}}: CS1 maint: archived copy as title (link)

External linksEdit

  • SUDS solutions from the British Geological Survey
  • International Best Management Practices Database – Detailed data sets & summaries on performance of Urban BMPs
  • Portland Guide to Sustainable Stormwater – City of Portland, Oregon