Sewage Spills Signpost Blue Roofs for SuDS

FOLLOWING the revelation that there were 3.6 million hours of sewage spills into UK rivers and seas in 2023, ACO Building Drainage is urging local authorities to consider how they can protect their areas from sewerage system overflows.

At the end of March, the Environment Agency published its findings that sewage spills last year increased 54% compared to 2022. This is in part due to increased rain in 2023 overwhelming sewerage system’s capacities.

The data goes further, showing that – though storm overflows are intended as an emergency relief to be used during extreme weather – over 86% of monitored stormwater overflows spilled during 2023, with 60% spilling more than 10 times.

Sustainable Urban Drainage Systems

Kevin Bohea, MD at ACO, recommends that local authorities ensure Sustainable Urban Drainage Systems (SuDS) are properly implemented. The need for SuDS is especially acute in dense urban environments with combined sewer systems. Slowing and reducing stormwater into these systems could significantly reduce sewage spills as well as flooding.

He said: “It is upsetting to once again see news that sewage systems are consistently overflowing. The impact on the environment and the potential flood damage to property is a real worry, one that the principles of SuDS can have a huge positive impact on. These principles see rainwater being contained safely before it’s slow release, lowering the pressure on sewage systems and reducing the likelihood of overflows, especially during storms.”

Blue Roofs

SuDS-based solutions such as blue roof systems can lower the impact of rainfall on sewerage systems. It means they can reduce the risk of sewage spills and flooding. Blue roofs provide a space on rooftops that stores rainwater before releasing it more slowly.

Kevin Bohea continued: “There is a common misconception in the industry that drainage discharge flow rates cannot be lower than two litres per second. While that’s true in some cases, many developments could accommodate SuDs components with lower flow rates which would benefit inner city combined sewers, thereby reduce flooding and protecting the environment. Local authorities can set planning conditions to avoid flooding and help the environment and we urge them to prescribe sustainable drainage systems for their schemes.

“Flooding in the UK is getting worse and the use of SuDS-based solutions provide a way of mitigating their impact,” Kevin ends.

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