The £3m project at Tunstall Reservoir, in Wolsingham, included maintenance and resilience work at the site, building in enhancements to the dam and spillway that will add protection in the case of emergencies.
Working with partners Esh-Stantec, the water company filled 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.
Work started in the summer of 2023.
A new transfer pipe was also installed within the structure of the dam, meaning water could be safely drained down from the reservoir more quickly in case of emergencies, helping to lower levels more rapidly and increase safety.
The new water pipe can transfer water from the west side of the dam, across to settlement tanks, before the water enters the spillway on the eastern end, into Waskerley Beck, and downstream to the River Wear.
On the spillway itself, concrete slabs were overlaid on old stone blocks, to further preserve the structure.
Finally, new survey points have been installed on the dam to help monitor any movement in the structure.
While Tunstall Reservoir is no longer a direct part of the water supply network, following the closure of the neighbouring water treatment works in 2003 it is an important environmental facility, used to help regulate water levels in the River Wear.
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.
“We would like to thank visitors to the site, who will have noticed our work being carried out at this beautiful Weardale setting. The team are now clear of site and we hope people will continue to enjoy visiting Tunstall for generations to come.”