The Thames Tideway is a massive infrastructure project to excavate a deep level interceptor sewer to store and transport waste water across London, much of which currently overflows into the River Thames. The deep level tunnel will run from Acton to Abbey Mills - a distance of around 25 kilometres. The tunnel depth at Acton is about 30 metres, descending to 66 metres at its terminus. The tunnel has a diameter of 7.2 metres. At the Abbey Mills terminus, the waste water will enter the existing Lee Tunnel and will be treated at Beckton Sewage Works.
Construction is taking place using six Tunnel Boring Machines (TBMs) and a total of 24 construction sites have been established. The giant TBMs were built in Germany and France and after arriving on site by barge were assembled on site. Many of the spoil extraction points are adjacent to the River Thames and barges are also being used to remove the spoil and minimise the impact on London’s roads.
One of the largest construction sites is adjacent to Blackfriars Bridge, near to where the culverted River Fleet flows into the Thames. The map marker pin has been located here, where a drop shaft will take the Fleet flow down to the new sewer.
The project is being managed by Bazalgette Tunnel Limited (BTL), a consortium whose name is a refrence back to the original creator of London’s sewer network. The project has an estimated cost of £4.1 Billion and is scheduled for completion in 2025.