Water & Wastewater Treatment

www.wwtonline.co.uk | WWT | NOVEMBER 2015 | 17 Project focus Pipes and pipelines Tunnelling helps SE Water complete vital new pipeline Project focus S outh East Water is set to complete a £8.1M pipeline project which has seen it tunnel under the River Medway, a railway line and the M20 motorway. The water company has used a 25-tonne Tunnel Boring Machine (TBM) for the two crossings, which form the most crucial part of a new ● New 7km pipeline to ensure better water supply in Kent ● Tunnel Boring Machine used to cross M20 and River Medway ● Environmental work safeguards Leybourne Lakes Country Park in the last four years; its inaccessible location, within an environmentally protected area, made it particularly difficult to locate and mend these bursts leading to disruption to customers. The route for the replacement pipeline, which is made of ductile iron with a diameter varying between 300mm and 600mm, has been years in the planning. It avoids Burham Marshes but passes through two local wildlife sites, Leybourne Lakes Country Park and Bushey Wood, as well as residential areas such as Ditton and New Hythe Business Park. The first phase of construction work began in January, with the pipeline expected to be finished in January 2016. In addition to passing under several small streams, the route involves two major crossings – one under the M20 and the other under both the River Medway and a railway line. For these tasks SE Water and its contractor Farrans opted to bring in a £500,000, 4.5m long Herrenknecht Tunnel Boring Machine, specially made in Germany and christened Molly by a member of staff. Chris Love, South East Water Delivery Manager, says: "Molly is two metres in diameter and a smaller version of the machines that dug the Channel Tunnel in the late 1980s. It's the first time we've used a machine of this size as part of a water main 7km pipeline to secure water supplies to Maidstone, Larkfield, Aylesford, Ditton and Snodland in Kent. South East Water's biggest AMP6 project, the pipeline is required to replace a Victorian cast iron water main which crosses Burham Marshes. The main is coming to the end of its design life and has burst nine times Lowering the Tunnel Boring Machine into the sha for the M20 crossing By James Brockett

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