Tackling Storm Overflows Together
Early progress but lots more to do
Our rivers and coastline mean so much to all of us in the South East.
Having spent many years swimming off this coast, diving in the sea and playing in the rivers, I share that passion. I’m determined to take on the challenge and set Southern Water on a path to help create cleaner rivers and healthier seas. Central to that mission is the challenge of cutting the number of storm overflow releases (also known as spills).
Five years ago we set up a team of experts called the Clean Rivers and Seas Taskforce to analyse storm overflow releases in detail and find out what action we could take that would have the biggest impact in reducing the number of spills. Their work informed our Clean Rivers and Seas Plan, under which we’re spending £1.5 billion to reduce overflow releases across the region. The plan brings together sustainable drainage, smarter tech, sewer sealing and upgrades across the network.
We’re still in the early stages of delivering the Clean Rivers and Seas Plan, but in just 12 months our work has prevented more than 700 storm overflow releases. We have much further to go, of course; but we’re moving quickly.
It’s a popular misconception that storm overflows are a new problem. They aren’t – this is how combined sewer systems work when they’re overwhelmed with rainwater. A single heavy downpour can send millions of litres of run-off from roofs, roads and pavements into pipes, mixing with sewage and overloading the system. In chalk areas, rising levels of winter groundwater forcing its way in can make the problem even worse, sometimes multiplying by ten times the volume coming into our treatment works. When too much water gets into the system all at once, storm overflows act like a safety valve to stop sewage backing up into homes, schools and streets.
That doesn’t make spills acceptable; but it shows that the real challenge is keeping rainwater and groundwater out of the network in the first place. So this is where we’ve put a lot of our effort. Let me give you some local examples of the approaches we’ve taken which are working and helping cut storm overflow releases:
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In Hampshire, we’ve disconnected more than 200 properties from the combined sewer.
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On the Isle of Wight, we’ve added smart sewer gates and upgraded pipework.
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In Kent, we’ve reconfigured our Swalecliffe site to manage flows better.
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In Sussex, we’ve sealed 20km of pipes to stop groundwater getting in.
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And we’re working with eight councils and nearly 100 schools to divert more than 120 million litres of rainwater away from the network.
These steps are making a difference. Climate change, population growth and new development are all continuing to add pressure, and we can’t fix this on our own.
Real, lasting change depends on us working together with councils, highways teams, developers, landowners, communities and environmental groups to effectively change the water system and prevent rainwater getting into the sewers. Our most successful projects have all been delivered in partnership.
It might not seem like it given news headlines, but wastewater management has actually changed hugely since thirty years ago, for the better. Back then, on the coast most sewage was released straight out to sea with little or no treatment. Today, in a typical year around 96% of wastewater is fully treated before it reaches the environment. That’s because Southern Water has spent £10bn building wastewater treatment plants right across the region’s coastline. The remaining 4% of wastewater is what’s released without full treatment into the environment through storm overflows, when they activate to prevent homes from flooding as the system becomes overwhelmed. This last 4% still represents a significant volume and it absolutely needs fixing -- which is exactly what we’re doing.
The action we’ve taken has also improved the quality of bathing waters right across the south east. Thirty years ago only around a third of our designated locations met minimum quality standards; now 94% meet the standards, and 89% of our bathing waters are rated “Good” or “Excellent”.
I know people want to see change now -- and we’re working fast to do this -- but it’s going to take time. I’m committed to being transparent with everyone who wants to enjoy our beaches and rivers. That’s why we publish information on storm overflow releases, including whether they’re likely to cause an impact to bathing water quality, on our app, Rivers and Seas Watch. This data also informs the Surfers Against Sewage’s Safer Seas app.
We’re determined to deliver the improvements our customers want and deserve. We’ll keep listening, learning and being open -- about both the progress we’re making and the challenges we still face. Through working together, we can create the cleaner rivers and seas everyone in our region wants and deserves.