Work has started on United Utilities’ £48M scheme to upgrade the sewer network around Knutsford in Cheshire and improve local water quality.

Led by principal contractor Ward & Burke, the first phase involves tunnelling a 1.8km underground pipeline from the Moor Pool pumping station to the Knutsford wastewater treatment works. The shaft-and-tunnel design will be up to 2m in diameter and reach about 20m below ground at its deepest point. United Utilities says the tunnel will store up to 5.5M litres of stormwater during heavy rainfall before the flow is processed at the treatment works.

A central compound for the tunnelling operation has been established off Parkgate Lane in Knutsford. Temporary traffic management and changes to pedestrian walkways will be in place during construction; the company says access to a nearby children’s playground will be maintained.

A second phase of work will target the health of the local watercourse. In partnership with Natural England and Tatton Estates, specialists Stonbury will carry out health checks on fish in Moor Pool and rehome them upstream in Peover while contractors remove accumulated sediment from a section of the river. United Utilities says the clearance will restore the pool’s health and improve water quality, and that fish will naturally repopulate the area from downstream on completion. The project is due to finish in May 2027.

United Utilities frames the Knutsford work as part of a broader investment drive in the North West. The company plans to spend more than £13bn during the five-year AMP8 regulatory period on water and wastewater infrastructure, including measures it says will protect and enhance more than 500km of rivers, lakes and bathing waters and safeguard drinking supplies.

Local residents and environmental groups will be watching the works closely. Large-scale stormwater storage and river dredging can reduce flood risk and pollution discharges when properly designed, but river sediment removal and the temporary relocation of wildlife can also raise concerns about ecological impacts if not carefully managed. Natural England’s involvement suggests regulators will have input to the fish relocation and habitat restoration measures.

Sean Reid, United Utilities county business lead for wastewater in Cheshire said: “This project highlights our ongoing commitment to improving water quality in the county, and how working closely with partners can offer alternative and innovative solutions to stormwater management in protected areas.

“On completion, this scheme will store up to 5.5M litres of stormwater in periods of heavy rainfall – that’s equivalent to two Olympic sized swimming pools.

“We understand that our construction work can be inconvenient, and our teams will do their best to minimise that disruption to the community, environment and park users.”

Tatton Estate sustainability and partnerships director Annette McDonald said: “This project has been shaped through extensive consultation and partnership working. We would like to thank United Utilities, Natural England, Liverpool John Moores University and Binnies for their expert contributions, which have given us confidence that this approach will minimise environmental impact while supporting the long-term restoration of the SSSI.

“Protecting the health of Moor Pool, improving water quality and safeguarding the wildlife that depends on it are vitally important to the Estate and we welcome the collaborative approach being taken.”

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