Environmental impact
During heavy storms, high volumes of rainwater could enter the sewer network in Frampton Cotterell via the combined system, which carries both foul water from homes and businesses and rainwater from roof gutters, patios, driveways and some highways together in one pipe.
These excess flows could sometimes cause sewers around the village to become overwhelmed before the combined sewage could be transported to a water recycling centre to be treated, causing a potential flooding threat to nearby properties.
Designed as a relief valve to protect homes from this flooding, storm overflows – part of the country’s sewer system for more than a century – automatically discharge this mix of diluted wastewater before treatment if the network is overwhelmed.
As part of 13 priority projects we identified in line with our commitment to progressively reduce and eliminate the discharge of untreated water, we devised a trio of solutions to help protect the precious ecology in and around the River Frome in the village.
What we did
Our teams planned and delivered projects at three separate sites in Frampton Cotterell to ease the impact of excess flows into local sewers.
The first of them got under way in April 2024, with the six-month installation of a £1.5 million storage tank, capable of holding as much as 225,000 litres of water on land next to the Frome Valley Walkway off Church Road in the village.
A small section of the Frome Valley Walkway was diverted during the Church Road construction and we reinstated the area, including a memorial bench, when completed.
Similar projects near Nightingale Lane and Watley’s End saw 180,000 litres and 480,000 litres of storage built below ground later that summer, an investment of more than £5 million in nearly one million litres of extra storage.
The schemes were completed early in 2025.
Involving the community
We wrote to customers and businesses throughout Frampton Cotterell about these projects and held a public drop-in session about the Church Road scheme, which was a deep excavation next to the River Frome, to answer questions from members of the public.
Our project team also briefed Frampton Cotterell Parish Council and local South Gloucestershire Council members, as well as the local Member of Parliament about the work.
How it is helping
Project manager Andy Roberts said: “These substantial investments into our sewer system in Frampton Cotterell will help to improve the quality of the River Frome by reducing times when untreated water reaches it via the automatic operation of storm overflows.
“By holding this excess water back in these tanks, we can then return it to the system later, via the Frome Valley Relief Sewer, so it can go onward to a water recycling centre for treatment.’’
What else are we doing?
Similar projects along the River Avon have also been completed, with storage tanks being constructed in Hanham near Bristol, Bradford on Avon in Wiltshire, Lambridge in the east of Bath and the Foxhill area of the city, as well as a storage tank in Saltford.
Our work to progressively and substantially reduce the discharge of untreated wastewater is continuing over the coming years too, with our plans for 2025-30 outlining a £580 million investment to reduce the operation of storm overflows, introducing more nature-based solutions and promoting better rainwater management. This is more than double the current investment.
We have asked the Competition and Markets Authority (CMA) to review how much we can invest in vital water and sewerage improvements over the next five years.
This comes after the industry regulator Ofwat’s final determination on our five-year business plan allowed for £4.2 billion of total expenditure – 17% short of what our own calculations have shown are required to meet our obligations and customers’ expectations, and support growth in the region.