01-08-2025
'You can hear it draining' - vanishing water at North Wales reservoir leaves people mystified
Walkers hiking past a serene lake have been startled to see an alarming dip in its water levels. Some have reported hearing the sound of water 'draining away' as if a plug had been pulled from beneath.
The former reservoir, on the hills high above Corwen, Denbighshire, is now listed as a 'tourist attraction'. However it still performs an important role, feeding a community-owned hydro-electric plant in the town centre opened in 2016 with its own purpose-built 'waterfall'.
Located within Coed Pen y Pigyn, the small reservoir is a popular focal point for walkers taking advantage of the area's excellent trails and vantage points. The oak woodland has animal sculptures and a Giant's Trail, along with a Gorsedd stone circle erected for the National Victory Eisteddfod in 1919.
The occasional red squirrel can be spotted scurrying around and a 12ft royal cairn with flagpole peers down on the town. This viewpoint is where Welsh prince Owain Glyndwr, in a fit of rage, is said to have hurled his dagger with such force it left its outline in a rock below.
As the reservoir has a thriving population of fish, fast-shrinking water levels have sounded local alarm bells.
Questions began appearing on social media earlier this week. 'Anyone know why the water level has dropped so much?' wondered one woman. 'Never seen it as low.'
Another insisted: 'I have never heard of the reservoir being drained to that point – and I've lived here all my life.'
Half-heartedly, this summer's drought was blamed for the water's mysterious disappearance, though human intervention was considered more likely.
The finger of suspicion fell on Dŵr Cymru Welsh Water, whose engineers had been spotted carrying out 'inspections' in the area.
Earlier this year the company completed a £9m upgrade to its Corwen wastewater treatment works. This was designed to reduce phosphate levels in the River Dee into which it drains.
However the work was independent of the reservoir, which is is not connected to Dŵr Cymru's water network.
The loss of water was first reported last week. At the time, a local man said: 'The Corwen reservoir is going down pretty fast through the stream part of the dam, not the overflow? Just wanted to know if this is normal?'
It wasn't. Dŵr Cymru has now confirmed it drained the reservoir to carry out remedial work. A spokesperson: 'Routine repairs are being carried out to the dam wall at Coed Pen y Pigyn.
'The management of water levels, already low following the recent dry weather, is allowing us to carry out the work.' Sign up for the North Wales Live newsletter sent twice daily to your inbox
The reservoir was last drained in 2020. That episode has left residents fearful of what might happen this time. 'The last time they did this, all the koi carp vanished,' sighed one person.
