Anglian Water has appointed civil engineering, infrastructure and tunnelling specialist Barhale to construct a £14.6 million twin pumped rising main featuring complex horizontal directional drilling (HDD) crossings beneath the East Coast Main Line and the River Great Ouse.

Photo: Supporting future development at Alconbury Weald, the new rising main will pass to the east of Huntingdon.

The new 7,460m pipeline will provide the wastewater network capacity to meet future development at Alconbury Weald in Cambridgeshire. Centred on the former RAF Alconbury base, the fast-growing new town has planning permission for up to 190,000m2 of employment floorspace and approximately 6,200 homes with supporting infrastructure and facilities.

Work will be delivered through the @one Alliance, the strategic delivery vehicle for Anglian Water’s Integrated Main Works programme, with civil engineering, MEICA and infrastructure specialist Barhale acting in the role of prime contractor.

The twin pipeline will be laid at diameters of 400mm, 315mm and 250mm, predominantly in open-cut, around the eastern side of Huntingdon. 1.5km will pass through the development site with the remainder mainly crossing agricultural land. The route avoids the disruption a more direct route through Huntingdon town centre would cause. The pipeline will discharge directly into Huntingdon Water Recycling Centre inlet works.

To meet growth projections, the new network infrastructure will require capacity for a volumetric load of 3840m3/day at a flow rate of 144l/s.

An existing pumping station at Alconbury Weald does not have sufficient capacity so developer Urban&Civic will build a new terminal pumping station.

HDD will be used at 10 locations, including a complex crossing of the East Coast Main Line, where Barhale will install twin 355m-long 630mm sleeves to slipline the 400mm pipe, and beneath the River Great Ouse, where twin 292m-long 400mm sleeves will accommodate the 250mm pipeline.

At the River Great Ouse crossing, Barhale will use track mats and Bailey bridges to cross drainage dykes and to avoid the archaeologically sensitive ridge and furrow feature.

To improve materials management and safety along the almost 7.5km-long site, Barhale will also trial use of a new Wacker Neuson off-road dumper with a skip change system. When not operating as a conventional dumper, in can be fitted with a flatbed offering greater carrying capacity than a standard pickup truck while providing off-road capability.

Ashley Jordan, Construction Manager, Barhale, 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.

“While the majority of the pipeline will be laid in conventional open-cut, the HDD installations beneath the East Coast Main Line and the River Great Ouse are quite challenging, particularly given the relatively wet ground conditions.

“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."

The project is scheduled for handover to the developer in November 2027.