Education & Advice - Background

Prevention & Controls


Good housekeeping and site design can reduce and manage runoff and pollution. This approach uses best practice to prevent pollution, by improving working practices that may cause pollution, or producing or using less polluting materials. For example ensuring waste water from cleaning activites such as vehicle washing are not discharged into surface water systems.

Prevention also includes measures that reduce the prospects of flooding, for example by minimising paved areas.

Source controls

These facilities control run-off at, or close to, the source (ie where rainfall lands on a surface). Examples include green roofs, rainwater harvesting , filter trenches and permeable or porous surfaces, such as permeable paving or grasscrete.

Site controls

Runoff is managed in a network across a site or local area. These are local facilities that receive run-off, often with several inlets and only one controlled outlet. The types of SuDs used are similar to Regional control examples; differing only in scale. The SuDS techniques suitable for these controls include detention basins, small ponds and French Drains. Also, flow should be slowed using overland conveyed routes.

Regional control

These are much larger “downstream” features that collect run-off. They should not receive significant pollutants; which are best managed by upstream facilities. Where possible, regional controls should be used as landscape features and provide final ‘polishing’ of the treatment train prior to discharge. SuDS techniques suitable at this scale include large retention ponds and wetlands.

You can find out more about these solutions by clicking here

A database of existing SuDS sites from across Wales has been set up to gather knowledge and experience and to make this information more widely available.

Cyfoeth Naturiol Cymru / Natural Resources Wales Welsh Water / Dwr Cymru Welsh Government / Llywodraeth Cymru Atkins Welsh Local Government Association Consumer Council for Water
Home Builders Federation CIWEM Institute of Civil Engineers