Barhale will build a £14.6 million Alconbury Weald wastewater pipeline for Anglian Water, adding capacity for the growing Cambridgeshire development through a 7.46km twin rising main with ten horizontal directional drilling crossings.
The project will be delivered through Anglian Water’s @one Alliance, with Barhale acting as prime contractor.
The new pipeline will run around the eastern side of Huntingdon and discharge directly into Huntingdon Water Recycling Centre.
Alconbury Weald wastewater pipeline to support development growth
The twin pumped rising main is being constructed to provide additional wastewater network capacity for continued development at Alconbury Weald, on the site of the former RAF Alconbury base.
The supplied project information states that the development has planning permission for approximately 6,200 homes and 190,000m² of employment space, alongside supporting infrastructure and community facilities.
The new wastewater infrastructure is being designed for a volumetric load of 3,840m³ per day at a flow rate of 144 litres per second.
An existing pumping station at Alconbury Weald does not have sufficient capacity to meet projected demand, with developer Urban&Civic due to construct a new terminal pumping station.
Further information about the wider development is available from Urban&Civic.
Ten HDD crossings planned along 7.46km route
The twin pipeline will use pipe diameters of 400mm, 315mm and 250mm and will be installed predominantly using conventional open-cut construction.
However, horizontal directional drilling (HDD) will be used at ten locations where the route needs to pass beneath or around sensitive infrastructure and environmental features.
One of the most complex crossings will take the pipeline beneath the East Coast Main Line. Barhale plans to install twin 355m-long, 630mm sleeves through which the 400mm pipeline will be installed.
A further HDD crossing beneath the River Great Ouse will use twin 292m-long, 400mm sleeves to accommodate the 250mm pipeline.
The route has also been selected to avoid the disruption that would result from taking the infrastructure through Huntingdon town centre.
River Great Ouse works designed around sensitive landscape
At the River Great Ouse crossing, Barhale plans to use track mats and Bailey bridges to cross drainage dykes while avoiding an archaeologically sensitive ridge-and-furrow feature.
Around 1.5km of the pipeline will pass through the Alconbury Weald development, with most of the remaining route crossing agricultural land east of Huntingdon.
The combination of open-cut installation and trenchless crossings is intended to allow the pipeline to pass beneath major transport and river infrastructure while limiting surface disturbance at the most constrained locations.
New rising main to connect with Huntingdon Water Recycling Centre
The pipeline will discharge directly into the inlet works at Huntingdon Water Recycling Centre.
Rising mains are pressurised wastewater pipelines used to transfer flows from pumping stations towards treatment infrastructure. H2O Global News has previously examined how Anglian Water monitors rising main performance across its wastewater network.
The Alconbury Weald scheme sits within Anglian Water’s wider AMP8 investment programme. The utility says its @one Alliance is expected to deliver around £3 billion of water and water recycling projects between 2025 and 2030.
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.”
Barhale will trial use of a new Wacker Neuson off-road dumper with a skip change system at Alconbury Weald.
Off-road dumper trial planned during construction
Barhale will also trial a Wacker Neuson off-road dumper with a skip-change system during construction.
The machine can operate as a conventional dumper or be fitted with a flatbed, which the contractor says will provide additional materials-carrying capacity while retaining off-road capability along the almost 7.5km construction corridor.
The project is scheduled for handover to the developer in November 2027.
Source: Barhale
