South East Rivers Trust (& the Wandle Trust)


What are SuDS?

Sustainable drainage systems (SuDS) are features installed to reduce the risk from surface water flooding.  SuDS capture runoff from surfaces like roofs, roads and pavements to prevent the drainage network from becoming overwhelmed.  Rainwater is diverted into features such as rain gardens, planters or storage under permeable paving.  These features reduce the quantity and slow the flow of runoff to the drains as well as filter out contaminants before the water enters the drain and flows into the river. 

Rain Garden

Why are SuDS needed?

In a natural landscape, rainwater is able to be useful. It can soak into the ground so plants can use it. It pools in ponds and wetlands, creating wildlife habitats.  Some of it soaks deep into the earth where it is stored as groundwater.  A small amount of rainwater becomes surface water runoff, flowing into rivers and out to sea.  However, as more and more of the natural landscape is built over, this natural flow of water is disrupted.

In built up areas, rainwater is prevented from soaking into the ground. Most rainwater becomes runoff. The rainwater that lands on roofs, roads, pavements and car parks rushes to the drains which empty out into the river. Not only could the river burst its banks but drains could overflow.  The drainage network was not built to cope with all this runoff. SuDS aim to restore the natural water cycle, allowing rainwater to soak in.  

Why install SuDS in schools?

SuDS in schools can:

  • Reduce flood risk
  • Ensure water entering the river is cleaner
  • Save water from going straight down the drain
  • Improve playgrounds spaces with new and interesting features
  • Increase opportunities for cross-curricular outdoor education
  • Improve the area for wildlife
  • Educate pupils and the wider community about surface water flooding

Considering SuDS for your school?  Useful guidance can be found here