A £2.7m maintenance and safety project at a County Durham reservoir is set to start this summer. 

Northumbrian Water is investing in the works at the dam and spillway of Tunstall Reservoir, in Wolsingham, following months of preparation and ground investigations.


Working with partners Esh-Stantec, the water company will fill an old shaft and tunnel, originally designed for drainage purposes, with expert support from mine rescue teams being required due to the necessary confined space working.


Additionally, a new transfer pipe will be installed within the structure to increase the amount of water that can be drained down from the reservoir in case of emergencies, helping to lower levels more quickly and increase safety. This will transfer water from the west side of the dam, across to settlement tanks, where silt is removed before the water enters the spillway on the eastern end, into Waskerley Beck, and downstream to the River Wear.


Most visible of the work will be on the spillway, where concrete slabs will be overlaid on old stone blocks, to further preserve the structure.


Finally, new survey points will be installed on the dam to help monitor any movement in the structure.


To enable the project to take place safely, the process of lowering the reservoir’s water levels will begin in advance of site work commencing in July. Work is scheduled to be completed in early 2024.


Paul Wood, Northumbrian Water’s Project Manager, said: “This essential maintenance will help ensure the future resilience of the dam at Tunstall Reservoir, as well as enhance our ability to react quickly in the case of any emergency.


“This is a really popular spot for visitors, in the heart of beautiful Weardale, and we know that those familiar with the site will notice the lower levels, but rest assured this is for the safety of those working on the project.


“We apologise for any inconvenience to those who enjoy the site and will be working to minimise any disruption around the reservoir itself while this work takes place.” 


Updates will be posted at www.nwlcommunityportal.co.uk 

throughout the project.