SUDS

[meanjean]

After the floods a couple of years ago, it is time local authorities took Sustainable Drainage Systems (suds) more seriously. It is now widely accepted that the drainage of developed areas by conventional piped systems is not sustainable. The piped system is designed to take away surface water from urban areas as quickly as possible without any thought what happens down stream. The use of SUDS techniques reduces the potential of flooding on new and existing developments and, unlike traditional stormwater drainage systems, also helps to protect and enhance ground water quality. SUDS employ a whole suite of techniques to effectively manage drainage at source including dry ditches (swales), detention/attenuation ponds, and integrated constructed wetlands, all of which aim to detain run-off and release it slowly into watercourses or to ground. Source control techniques are also increasingly popular - such as the use of porous (as opposed to impermeable) paving and 'green roofs' which allow rainwater re-use. To date almost all SUDS implementations in the UK have been associated with new developments, but we can all do our bit. Prevention plays an essential part in surface run off. The prevention of run-off requires careful consideration of the need to pave a surface – a gravel surface for a car park may be an acceptable alternative – and the disposal of roofwater. For example, it may be possible to discharge roofwater onto a lawn, where it can soak into the ground. The need for surface water drains and off-site sewers can be reduced or eliminated where run-off is encouraged to permeate through a porous pavement, such as permeable concrete blocks, crushed stone or porous asphalt.