What are sustainable drainage systems?

Sustainable drainage systems, or SuDS, are a way to prevent surface systems from becoming overwhelmed or polluted during heavy rainfall.

They work by reducing the amount of standing water on hard surfaces like roads and pavements, delaying surface run-off from entering drains and sewers, and preventing contaminated water from reaching natural waterways.

SuDS – which is sometimes used to refer to sustainable urban drainage systems – have become an important part of planning in more densely populated areas, where a significant percentage of land is covered by roads and buildings.

There isn’t just one SuDS technology. Rather, the term relates to a number of commonly used techniques which, together, help to prevent and spread out surface run-off and wastewater that would otherwise enter drains, sewers and rivers in large quantities.

Five common SuDS techniques

SuDS can work in several ways:

  • Catch rainwater so it can be directly reused.
  • Divert contaminated surface water away from natural waterways into storm drains.
  • Delay large quantities of run-off to prevent flash floods.

Five common SuDS techniques that help to achieve one or more of these main aims are:

1. Swales

Swales use soil and vegetation such as grass to provide a soakaway for surface run-off. They are popular in urban environment design where grass verges and other green areas along roadsides are already common.

2. Retention Basins

Another common feature of urban areas, retention basins provide a place for floodwater to accumulate before it is released in safe quantities. This can help to prevent downstream flooding during heavy rainfall.

3. Wetlands

Wetlands and nature reserves can serve as a place for surface water to collect. Artificial wetlands can help with urban SuDS efforts, and usually do not rely on using a pumping station, but instead use the ecology of the habitat to disperse the surface wastewater.

4. Green Roofs

Green roofs are a way to deal with excess rainfall on buildings, which would normally be sent directly into the sewers via gutters and drainpipes. They use vegetation to catch the falling rain – although it’s important to make sure older roofs can support the weight.

5. Permeable Paving

An increasingly common SuDS technique is permeable paving, such as Grasscrete which allows rainfall on hard surfaces to penetrate into the ground below, instead of staying as surface run-off. This can be achieved using a permeable membrane beneath the paving, and by using permeable paving materials or leaving small gaps between pavers.

Find out more

If you want to know more about sustainable urban drainage systems, or if you have problems with standing water during heavy rainfall, contact us today on 0151 2360707 and we’ll be happy to discuss suitable SuDS options with you.

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