Barhale has been appointed by Anglian Water to construct a £14.6m twin pumped rising main that will provide additional wastewater capacity for the expanding Alconbury Weald development in Cambridgeshire.
The 7,460m pipeline will be delivered through the @one Alliance, Anglian Water’s strategic delivery vehicle for its Integrated Main Works programme, with Barhale acting as prime contractor. The project is scheduled for handover to developer Urban&Civic in November 2027.
Route crosses railway and river
The twin main will use 400mm, 315mm and 250mm diameter pipes, with most of the route constructed using open-cut methods around the eastern side of Huntingdon. About 1.5km will pass through the Alconbury Weald development site, while the remainder will mainly cross agricultural land.
Horizontal directional drilling (HDD) will be used at 10 locations, including crossings beneath the East Coast Main Line and the River Great Ouse. At the railway, twin 355m-long, 630mm-diameter sleeves will accommodate the 400mm pipe. The river crossing will use twin 292m-long, 400mm-diameter sleeves for the 250mm pipeline.
Barhale said the works will also require track mats and Bailey bridges to cross drainage dykes and avoid an archaeologically sensitive ridge-and-furrow feature. The route has been selected to avoid the greater disruption that a more direct alignment through Huntingdon town centre would cause.
Capacity for planned growth
The new network will discharge directly into the inlet works at Huntingdon Water Recycling Centre and is designed to provide capacity for a volumetric load of 3,840m³ per day at a flow rate of 144 litres per second. The existing pumping station at Alconbury Weald is not sufficient for the planned demand, so Urban&Civic will construct a new terminal pumping station.
Alconbury Weald, centred on the former RAF Alconbury site, has permission for up to 190,000m² of employment floorspace and about 6,200 homes, alongside supporting infrastructure and facilities.
Barhale construction manager Ashley Jordan said: “Housing and commercial growth, together with climate change and urban creep, mean the existing sewer network will no longer meet demand by 2027. This project provides the necessary additional capacity.”
Jordan said the HDD installations would be challenging because of the wet ground conditions. Barhale will also trial a Wacker Neuson off-road dumper fitted with a skip change system to improve materials handling and safety across the almost 7.5km-long site. The vehicle can be converted from a conventional dumper to a flatbed, providing off-road capability and greater carrying capacity than a standard pickup truck.
Jordan added: “We are looking forward to working with Anglian Water and our @one Alliance partners to deliver an asset that will futureproof the network to support the continued growth of Alconbury Weald.”