The aim of a sustainable drainage systems to drain away surface water runoff through collection, storage and cleaning before allowing it to be released slowly back into the environment, such as into water courses.
Sustainable drainage systems is a term that is now applied to both urban and rural systems, and includes natural and engineered structures.
There are many different sustainable drainage system features available to suit the constraints of a site. They include green roofs, and more natural features such as ponds, wetlands and shallow ditches.
Hard engineered elements are often used in high density, commercial and industrial developments. These include permeable paving, canals, treatment channels, attenuation storage and soakaways.
Clear benefits
Along the way to the nearest watercourse, any pollutants are reduced – including metals and hydrocarbons from roads and car parks. Water entering a local watercourse is cleaner as a result and does not harm wildlife.
Suds generally replace traditional underground piped systems that use grates or storm water drains at street level. This means any problems with the system are quicker and easier to identify than with a conventional system and are likely to be cheaper and more straightforward to rectify.
Our best practice suggestions
A contemporary sustainable drainage methodology should use focus on three key areas:
- Quantity - Controlling surface water (reducing off-site flow rates)
- Quality - Improving surface water
- Amenity - providing added development amenity value.
Provision of all three areas in equal measures will not always be possible, or necessary, but three key objectives should be developed as part of an integrated and sustainable surface water management strategy:
- Maximise a reduction in natural runoff by using infiltration techniques wherever feasible
- Manage the residual flood risk as well as reducing the total volume of surface water runoff discharged
- Maximise quality improvements in surface water runoff.
These guidelines can all be satisfied using natural or proprietary techniques, either alone or in combination. Speak to a member of our technical team for more information.
