Below is an update from Southern Water - 18.08.2022
After months of hot, dry conditions across the UK, where we have seen far-below average rainfall, the ground has hardened so that it cannot readily absorb moisture. Instead rainfall will run off the surface in our drains, adding additional pressure on our sewers.
This is what we saw happen yesterday when thunderstorms in the region brought very heavy rain which fell onto parched ground that couldn’t absorb surface run-off. This meant that more rain than usual overwhelmed our network and led to some overflows – which are used to protect homes, schools, businesses and hospitals from flooding – spilling excess water into the sea. Releases such as these are permitted and regulated by the Environment Agency, and heavily diluted; typically 95 per cent rainwater.
An additional issue is that in times of dry weather, heavier materials (rags, unflushables, grit, woody debris etc) settle and sit in the sewer. As heavy downpours hit, there will be then a sudden influx of wastewater into the sewer network which flushes out the sewer and clears the debris that has been sitting there, suddenly transporting it to pumping stations. This can lead to blockages forming, pumping stations getting clogged up and cause potential floods and storm overflows.
We provide near real-time information about storm overflow activity in coastal areas, via Beachbuoy, our near real-time reporting tool. You can find Beachbuoy on our website here.
We are dedicated to significantly reducing our use of storm overflows and are running innovative Pathfinder pilot schemes across the region to reduce the amount of rainfall entering our combined sewers by 2030. What we discover in our Pathfinder areas, will help inform our investment plans moving forward. For more information, please visit our Storm Overflow Task Force pages Storm Overflow Task Force (southernwater.co.uk)