In My Area

Planned improvements

Elan Valley Aqueduct - Severn Siphon



31 May 2018

Estimated completion date
Upcoming work
Work in progress
Work completed
Severn Siphon

Start of site preparation - May 2017

Severn Siphon

Site reinstatement complete - May 2018

Start date

17 May 2017

There are currently no disruptions

There are currently no disruptions

There are currently no disruptions


The Elan Valley Aqueduct (EVA) is over 100 years old and so is in need of some modernisation.

We cannot shut down the EVA to carry out work, as it provides a vital water supply for Birmingham. We are therefore building new bypass sections alongside the EVA at Bleddfa, Nantmel and Knighton where the EVA needs refurbishment.

To create each bypass a shaft is first built at either end and a 3 metre diameter tunnel boring machine is then driven underground to cut the new bypass tunnel between the shafts.

Once the bypass is complete the new section is connected to the EVA. This means most of the work is not noticeable above ground and can be completed without interruption to the EVA flow.

Tunnel Boring Machine at Bleddfa

Why are we doing this?