SUDS are drainage systems that are considered to be environmentally beneficial,causing minimal or no long-term detrimental damage. They are often regardedas a sequence of management practices, control structures and strategiesdesigned to efficiently and sustainably drain surface water, while minimisingpollution and managing the impact on water quality of local water bodies.SuDS take inspiration from natural features and processes like uptake of waterby plants, soil infiltration, pools, ponds, marshes, wetlands, springs, streams andrivers.SuDS work by holding rainwater back, treating pollution and releasing it slowly,without overwhelming the watercourse or sewer system into which it flows,thereby reducing flooding.SuDS are more sustainable than traditional drainage methods because they:

Manage runoff volumes and flow rates from hard surfaces, reducing theimpact of urbanisation on flooding

• Provide opportunities for using runoff where it falls
• Protect or enhance water quality (reducing pollution from runoff)
• Protect natural flow regimes in watercourses
• Are sympathetic to the environment and the needs of the localcommunity
• Provide an attractive habitat for wildlife in urban watercourses
• Provide opportunities for evapotranspiration from vegetation andsurface water
• Encourage natural groundwater/aquifer recharge (where appropriate)
• Create better places to live, work and play.

SuDS can take many forms, both above and below ground. Some types of SuDSinclude planting, others include proprietary/manufactured products. In generalterms, SuDS that are designed to manage and use rainwater close to where itfalls, on the surface and incorporating vegetation, tend to provide the greatestbenefits. Most SuDS schemes use a combination of SuDS components toachieve the overall design objectives for the site.