Barhale’s £18m Anglian stormwater scheme: design and constructability notes for engineers
Reviewed by Tom Sullivan
First reported on The Construction Index
30 Second Briefing
Anglian Water has appointed Barhale as principal contractor for an £18m stormwater scheme at Walton-on-the-Naze, centred on a new 5,000m³ “pill shaped” storm tank built in diaphragm wall construction adjacent to the existing terminal pumping station. The tank geometry is designed to avoid an existing aquifer and sewer, with excavation from within the wall to minimise the footprint on a constrained coastal site. Additional storage will be linked to the current tank via an 84m, 1,200mm concrete jacked pipeline installed by microtunnelling to manage extreme rainfall events and protect bathing water quality.
Technical Brief
- £18m capex package let under Anglian Water’s Integrated Main Works programme via the @one Alliance.
- Environment Agency and Anglian Water tracer studies quantified flow paths, underpinning the additional storm storage requirement.
- Investigations focused on preventing the terminal pumping station being hydraulically overwhelmed during extreme rainfall events.
- Design development had to accommodate an existing aquifer, driving non-standard geometry and construction sequencing.
- Diaphragm wall solution chosen to shrink excavation footprint and control groundwater ingress around the tank.
- Microtunnelled 1,200 mm pipeline in concrete jacking pipes reduces surface disruption between the two storage assets.
- Scheme is framed as a bathing water quality protection measure, tying storm storage directly to environmental compliance.
Our Take
Barhale’s repeat work for Anglian Water, including the recent Cypermethrin treatment upgrade at Raunds, signals that it is becoming a go‑to contractor for technically complex water-quality and stormwater schemes in the Anglian region rather than just one-off civils packages.
The use of a relatively short but large-diameter (1,200 mm) pipeline at Walton-on-the-Naze aligns with Anglian Water’s wider push, seen across other projects in our infrastructure coverage, to create high-capacity ‘shock absorber’ assets that can handle intense storm events without relying solely on network-wide upgrades.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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