Post by WaterProjectsOnline

JUST PUBLISHED: Gaskell Street CSO & Detention Tank Enhancing river quality in St Helens through innovative wastewater screening & storage Located in St Helens in the north-west of England, this project addressed a long-standing issue associated with a combined sewer overflow at Gaskell Street. Under storm conditions, the existing outfall regularly discharged stormwater into Sankey Brook, posing both environmental and regulatory challenges. The scheme was therefore driven by the requirements of the Environment Agency’s Storm Overflow Discharge Reduction Plan and delivered as part of United Utilities’ AMP8 Better Rivers Programme, which seeks to significantly reduce the frequency and impact of storm overflows across the network. The Gaskell Street CSO & Detention Tank was developed to reduce spill frequency to no more than an average of 10 rainfall events per year, ensure no local adverse ecological impact, and to provide 6mm solids separation up to the 1 in 5-year design storm critical flow rate with 2050 climate change allowance. At the heart of the scheme is the 12.5m ID, 10m deep in situ reinforced concrete sunk caisson shaft which provides 700m3 of storm storage. A key innovation was to combine the circular detention tank shaft and a rectangular CSO chamber into a single integrated structure; delivering considerable savings in programme and cost, and a meaningful reduction in embodied carbon. Flows are screened upon entry into the detention tank via a new CSO channel housing an Eliquo Hydrok 180° MecMex removable screen, 3m in length, sized to deliver 6mm solids separation for a design flow rate of up to 1500 l/s. The wider scope included constructing of a series of new manholes and connecting sewers to integrate the upgraded assets with the existing network, together with dedicated instrumentation chambers and associated monitoring equipment. The project was delivered to an accelerated 11‑month programme ahead of the March 2026 regulatory deadline, requiring careful management of complex ground conditions, including historic landfill and coal mining risks. Critical to the projects's success was close collaboration between Ward and Burke, United Utilities, and the key supply chain partners: JBA Consulting MGF Van Elle Lloyd Morris Electrical Ltd QUINSHIELD LIMITED ELIQUO HYDROK Shay Murtagh Precast Ltd. Tracey Concrete Ltd Electrosteel UK Paul Moore Xylem ALTHON LIMITED T Allen Engineering Services Ltd Rope and Sling Specialists C&D Engineering Technocover Ltd Siemens Chemglass Ltd Camfaud Concrete Pumps Ltd Cemex Nixon Hire Tyrer Ecological Consultants Ltd Bowland Ecology Ltd Treefellers Ltd SOCOTEC Lanes Group The project is a great example of how collaborative, forward-thinking design can deliver lasting benefits for the environment and the local community. Read the full case study: https://lnkd.in/ef2EEDen #stormwaterstorage #waterindustry #betterrivers