Water pipe diverted around road, rivers and rail lines

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Catford Works

A major tunnelling operation to divert a water main under the South Circular Road and around a river and two railway lines has been completed in south London.

The Thames Water project described as “like threading the eye of a needle” will enable the building of 588 apartments by Barratt Homes at nearby Catford Green.

The 11-acre site, formerly home to Catford greyhound stadium, had lain derelict for 10 years before being passed to the Greater London Authority. It has since been earmarked for redevelopment as part of the London Plan regeneration project.

But in order to make it happen, Thames Water had to find a way to divert a main carrying water from a borehole in Ladywell Fields, Catford, to Kangley Bridge water treatment works in Beckenham.

Project manager Rob Gauldie said: “The site is sandwiched between two railway lines and we also had to avoid a lot of densely-packed underground utility services, a railway bridge with deep foundations and the South Circular highway.

“Designing a route for the pipe was very much like threading the eye of a needle.”

Thames Water looked at a number of options for carrying out the work, before deciding on a lightweight drilling rig – delivered brand new from the USA – together with an AC electromagnetic guidance system to steer the drill head along the 250-metre tunnelling route.

Rob added: “It was difficult to track the drill because of interference from the railway lines and from the reinforced concrete culvert which carries a section of the Ravensbourne River. This could have led to some significant delay. However, we were able to work with our supply chain to find the right answer to the problem.

“The team put in a huge effort to overcome these challenges, working nights and weekends to support our customer’s programme. It was a massive relief to hear at 4am one Saturday morning that the pipe has been successfully pulled through.”

The redeveloped site is due for completion in summer 2018.