Gatehampton Borehole Upgrade
- Sector: Raw Water & Sewerage
- Product: Excel (PE100)
- Client: Thames Water
- Contractor: Black and Veatch
Thames Water used Excel pipes as part of Gatehampton Borehole Upgrade, the largest groundwater abstraction project in Europe.
The Gatehampton Borehole Upgrade Project is part of the Thames Water GATOX (Gatehampton to Oxford) scheme, which helped to boost the amount of water available for customers in Swindon and Oxford from 87 to 105 million litres a day (average).
This took effect in June 2009 when a surge vessel has been installed to protect the main to Cleeve.
The largest groundwater abstraction project in Europe, Gatehampton comprises seven boreholes. When linked to form a ring, they provide substantially increased flow management to the Cleeve Water Treatment Works.
The supply of polyethylene pipes to Thames Water’s Gatehampton Borehole Upgrade Project has called for a measured approach by GPS PE Pipe Systems. Pipework operating pressures and local access restrictions were studied in depth by the manufacturer, before delivering the best-value/cost solution.
One of the difficulties faced by the contractor, Black and Veatch was that new pipes had to be installed within a small village, Goring-on-Thames. GPS investigated the delivery route to assess the problems of transporting pipe lengths around narrow access roads and tight bends.
As a result GPS produced and delivered the pipe in 12m lengths, rather than the 18m option, more typical of large installations. The company’s diligent groundwork was recognised and GPS was awarded the order for the full scope of sizes on the project, from 355mm up to 800mm.
Analysis of the new pipework scheme by GPS design engineers, working with the project team, led to the specification of Excel (PE100) pipe in SDR17, which denotes the relative wall thickness of the pipe and strongly influences its pressure rating. Installed by open-cut, the PE pipes simplified the installation procedure through their ability to be ‘snaked’ into the trenches, as flexible pipe strings with very few mitred joints.
In total some 1600m of butt-fusion jointed PE pipe were required to complete the work. Although the new pipe was not originally included the project, delamination and bursts in the locality’s existing GRP pipes created the need for a system replacement. Thames Water favoured polyethylene as the most suitable material to handle pressure surges from the boreholes.
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