Southern Water has published its Clean Rivers and Seas Plan, outlining proposals, underpinned by £1.5 billion investment between 2025-2035, to get to the root cause of storm overflows across its region.

Photo: Southern Water Clean Rivers & Seas Plan - Lawrence Gosden CEO

Storm overflows are part of the design of the water company’s combined sewer network, which captures both rainwater and wastewater. The emergency outlets are the last line of defence to stop homes and communities flooding when the sewer system becomes overwhelmed by large volumes of rain or groundwater entering the network.

According to the water company, out of almost 1,000 storm overflows in its region, 50% of these are already hitting the government’s 2050 targets, releasing 10 times or less a year.

The Clean Rivers and Seas Plan will be the blueprint for how Southern Water will address the remaining overflows. By 2035, 75% of its high priority overflows will be meeting government targets, reducing spills by an average of 8,000 a year, and by 2050 100% will meet these targets, the water company said.

The first phase of the plan will be delivered between 2025 and 2030 and will see an investment of £700 million to focus on areas such as shellfish and bathing waters, and environmentally sensitive sites. This means by 2030, spills will reduce by 3,000 a year.

The ‘Clean Rivers and Seas Task Force’ are a team of environmental scientists, engineers, and industry experts who have been leading on putting the plan together and testing nature-based solutions across the South-East. These solutions work in harmony with our natural environment, slowing the volume of rainwater going into the combined sewer, and making infrastructure improvements to increase our capacity. This includes rain gardens, wetlands, tree planting schemes, installing water butts in densely urbanised areas, and optimising our existing infrastructure.

Launching the plan, Southern Water said:

“We understand our customers want to see change now. We face tough choices in striking a balance between environmental protection and minimising the impact on bills for customers. Although customers will notice the impact reflected in their bills, the average water bill is one of the lowest household bills.

“Some of the work will take a long time, but we are committed to investing the time and expertise to go as quickly as possible. This is why we are asking our customers for their feedback on our Clean Rivers and Seas Plan here so they can tell us if they agree with how we are prioritising overflows in our region before we agree it with Ofwat, our regulator.“

The plan has been drawn up by the ‘Clean Rivers and Seas Task Force’ - a team of environmental scientists, engineers, and industry experts who have been leading on putting the plan together and testing nature-based solutions across the South-East.

These solutions work in harmony with the natural environment, slowing the volume of rainwater going into the combined sewer, and making infrastructure improvements to increase capacity. This includes rain gardens, wetlands, tree planting schemes, installing water butts in densely urbanised areas, and optimising existing infrastructure.

CEO of Southern Water, Lawrence Gosden, commented:

“I’ve heard our customers’ concerns, and we take our impact on the environment seriously. We have a long-term strategy to 2050 that will restore and protect our regions’ rivers and coastal habitats and a large part of that will be to get to the root cause of storm overflows.

“We cannot simply switch storm overflows off. But by implementing this Clean Rivers and Seas Plan and tackling the root cause, slowing the flow of rainwater going into the combined sewer, whilst increasing capacity of our network, we can reduce their use.”

“Collaboration is key, and we cannot achieve the results needed alone. That is why we are calling on our customers and local authorities to work with us and adopt solutions like water butts or sustainable drainage systems, to channel rainwater safely and slowly back into the environment. Together, we can go faster and further, protecting our communities and our environment.”

Click here to access the Clean Rivers and Seas Plan interactive map