Thames Water has awarded Barhale the contract to complete the final leg of the £17M Greenwich Trunk Main scheme, securing water supply and improving network resilience for Southeast London.

Civil engineering, infrastructure and tunnelling specialist Barhale will deliver Phase Three of the 4km programme by installing the final 1km of ductile iron pipeline using open-cut from the Blackwall Lane roundabout to the O2 arena.

It follows the completion of Phase One (2.7km, Greenwich Park – Blackwall Lane roundabout) and Phase Two (80m across the new Silvertown Tunnel).

The Greenwich Trunk Main scheme connects to an existing 800mm diameter water main at Croon’s Hill. It crosses Greenwich Park and then continues to the Peninsula. Phase One was the largest construction project undertaken in the park since the 2012 London Olympics. The driver for this project is the need to increase water network capacity within the Greenwich Peninsula area, which is experiencing significant developer growth.

Phase One will be commissioned in Q4 2026; Phases Two and Three in May 2027. In a first for Thames Water’s infrastructure at this scale (350mm – 800mm diameter pipelines), Barhale will be working with specialist contractor Suez to use ice-pigging during commissioning.

Instead of swabbing and high velocity flushes, with ice-pigging the asset is filled with a slurry of ice and then water is used to push it through, removing unwanted material, sediment or product residues, whilst also saving 1,789,719 litres of water. After all sections are ice pigged, the pipeline is chlorinated.

Steve Collett, Contracts Manager, Barhale explained that the technique reduces the number of pits required and brings programme and environmental savings.

“Normally, to allow commissioning, we would have to dig pits wherever the pipeline changes size,” he said. “Across this project that would have meant 25 pits. Using ice pigging we can reduce that number to just 6, delivering £800,000 in savings on the project.

“Apart from the financial savings, we use less carbon, almost 1.8 million litres less water than regular flushing and can commission faster so there is less disruption for communities along the pipeline.

“We are pleased to have worked alongside Thames Water throughout the Greenwich project. New infrastructure, such as the Silvertown Tunnel and the Elizabeth Line, is encouraging housing and commercial development in this part of London. The new water main is an important upgrade to the network’s capacity which will ensure it is able to meet future demands.”

The project is expected to complete in July 2027.