Ten out of ten for Nine Elms

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Thames Water’s ambitious and innovative sustainable urban drainage system (SUDs) project in a high-profile corner of south London is testing the company’s alliances to the limit.

While the nearby American embassy is putting the finishing touches to its HQ on London’s South Bank, Thames Water’s eight₂O alliance is tasked with creating a network of drains very close by.

“We’ve asked them if they can share their plans for the building with us, to help us locate where we can and can’t dig down,” said Paul Clough, eight₂O’s project manager for the scheme. “They’ve said that’s classified.

“So we’ve had to say ‘how would it be if we dug down here?’ and they came back and said ‘OK’.”

It may not be an ideal situation but, where the Nine Elms development is concerned, it’s not untypical, either.

From the outset, this radical project to ease the pressure on an existing sewerage system by building a new pipe network to handle its surface water obligations has needed to be a model of teamwork and compromise.

“The project began with an approach in 2012 to Thames Water from the Nine Elms Partnership,” said John Hernon, from Thames Water’s developer services department. “The partnership, made up of Lambeth and Wandsworth councils, the GLA and developers Ballymore, wanted Thames Water to have a close look at everything that was planned in the Nine Elms area – the new US Embassy, the extension to the Northern Line, the Thames Tideway Tunnel and 21,000 new homes.”

It made sense for Thames Water to embark on a modelling project to examine its options. When that was done, the choice was clear – either build new sewers to cope with the additional demand, or establish an innovative SUDs to free up space in the existing sewers.

The second option, with reduced disruption in an already congested part of the capital, made perfect sense and, in October last year, Thames Water embarked on the £16m scheme.

To succeed, it’s meant close co-operation not just between Thames Water and the Partnership, plus other occupants of the site, like Royal Mail and the US Embassy, and the Environment Agency, but between the Infrastructure Alliance, which carried out much of the planning, and eight₂O, which is responsible for the construction work.

When it’s complete, scheduled to be the end of this year, the Nine Elms scheme will be the biggest SUDs project in the UK.

Instead of going into the sewer network, as at present, the SUDs will channel surface water from an area stretching between Vauxhall and Battersea Power Station, into large underground pipes and then, via an underground reservoir and a new pumping station, into the Thames.

Crucially, the big engineering project will be complemented by a variety of eco-friendly innovations, including green roofs, ditches containing filtering vegetation and streets with rainwater gardens, which will allow water to evaporate into the atmosphere, irrigate plants and reduce the volume of rainwater flowing back into the river.

Taken as a whole, it’s a complex, constantly demanding, endlessly challenging project but for Paul Clough, it’s hugely enjoyable and represents a steep learning curve. “It’s got a bit of everything,” he said. “We’ve had to squeeze ourselves in to a very small corner of London, but we’re earning the trust of everyone involved and getting the job done.

“When it’s finished, this will be something that Thames Water and the whole of London can be immensely proud of."