Channelling water to our taps: Severn Trent spends £300m to keep supply running
The third of three huge multi-million pound bypass tunnels to reinforce water supplies between the Elan Valley Aqueduct and the West Midlands, has been completed as part of a £300 million project.
The tunnel at Knighton is one of three created by Severn Trent, allowing it to divert water away from the Victorian Elan Valley Aqueduct so repairs can be carried out. The aqueduct has been bringing water to West Midlands for more than 100 years.
But after so many years of service, the need for regular maintenance and refurbishment has become ever more frequent and so extra support was needed for the aqueduct to make sure that it can continue to provide service for another 100 years.
So the Birmingham Resilience Project – Severn Trent’s flagship £300million programme, began in 2015.
The Knighton tunnel is one of three created by Severn Trent, allowing it to divert water away from the Victorian Elan Valley Aqueduct so repairs can be carried out.
Engineers started work in Knighton in July last year, having already completed work on bypass tunnels in Bleddfa and Nantmel.
They used a specialist tunnelling machine from Germany, three metres in diameter, to do the seven months of work and it has now finished.
The project is Severn Trent’s biggest ever scheme and combined with a new 25km pipeline from the Severn at Lickhill, it will allow them to take the Elan Valley Aqueduct out of service for up to 50 days every other year, so they carry out a full maintenance programme without threatening the supply to people in Birmingham.
Currently the EVA is the only source of water for Birmingham so it is really important work.
Paul Dennison, programme manager, explains: “At the moment, the EVA is the sole source of supply into Birmingham, and storage at our treatment works at Frankley means we can only turn it off for a few days at a time for maintenance.
“To allow us to turn it off for longer periods, an alternative water supply for the city is being built. Work has taken place on a new pipeline from Lickhill, near Stourport-on-Severn, 25km into the existing water treatment works in Birmingham.
“However, our checks on the existing aqueduct showed that in three places, there was work that we'd rather do before the new pipeline is completed. As we can’t shut down the aqueduct, we've had to come up with alternative solutions.”
Severn Trent has been working with its contract partner, BNM Alliance, since October 2015 when the Bleddfa Tunnel started and a launch ceremony was held in May 2016 to celebrate the arrival and launch of the Tunnel Boring Machine.
The machine broke out successfully in December 2016, completing the first tunnel.
All the tunnelling equipment from Bleddfa was then transferred to the second site at Nantmel, where the machine was relaunched in April 2017 to start work on tunnel number two. Finally, the machine was moved to Knighton where work began in July 2018.
Report by Karen Compton