Reservoir disasters warning in Wales as climate breakdown 'flashes red'

Reservoir safety in Wales has been thrust into the spotlight as signs of climate breakdown start “flashing red”. Valencia’s disastrous floods in Spain coupled with recent reservoir failures in the UK and US have heightened fears of a catastrophic event in Wales.

The country has 397 large raised reservoirs and collectively they store more than 700m cu metres of water. Of these, 266 are classed as “high risk”, including around 20 privately owned reservoirs, and 73 are considered non-compliant for issues such as safety, maintenance and monitoring.

With an average age of over 110 years, reservoirs pose a potential flood risk to more than 220,000 people. Infrastructure services such as roads, railways, bridges and utilities are also vulnerable.

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Natural Resources Wales (NRW) regulates reservoir safety but concerns have been raised over a lack of funding hindering its ability to carry out the job. Pushing the case for more money is Aberconwy MS Janet Finch-Saunders, who believes reservoir safety should have the same priority as that given to old coal tips.

She said: “With the recent devastating flooding seen in Spain, we have to be prepared for the increased risk of severe flooding here in Wales and the destruction it causes.

"Heavy rainfall is placing significant strain on Wales’ reservoir infrastructure. Some £25m has been offered for coal tip safety, yet private reservoirs are left to the responsibility of the landowner with no funding made available to support them.” More reservoir flooding projections in North and Mid Wales can be found here.

Last winter, NRW issued 483 flood alerts, up 16% on the previous year. UK winters are now 10% wetter, said Ms Finch-Saunders, and the trend is set to continue. Speaking in the Senedd (Welsh Parliament), she cited several reservoir disasters and near-misses that should serve as a warning of the looming threat. Join the North Wales Live Whatsapp community now

Most significant was the Dolgarrog tragedy in her own constituency where, in 1925, a dam breach, killed 16 people. More recently, in 2012, almost the entire village of Pennal, Gwynedd, was evacuated when cracks appeared in a small reservoir. A similar evacuation was ordered earlier this year when dam in Minnesota, US, failed after intense rain.

One of the most notorious near-misses of recent times was the partial collapse of the “fully compliant” dam at Toddbrook reservoir in Derbyshire in 2019. This led to 1,500 people being evacuated from nearby Whaley Bridge for several days. The resulting review identified weaknesses in Britain’s existing reservoir safety regime, and on November 4 the Welsh Government announced that NRW would work with England’s Environment Agency to reform reservoir safety standards.

At the time Huw Irranca-Davies, cabinet secretary for climate change and rural affairs, said this approach aims to modernise reservoir monitoring in Wales, reduce the risk to communities downstream and to ensure reservoirs can cope with climate change. Yet while NRW is acting on concerns identified, critics claim too little is being done too slowly.

Around 20 high-risk reservoirs in Wales are owned privately and half are due for review within the next five years. There is concern they lack the resources to remedy any issues identified. Several are classed as “orphans” - ownership is not known - leaving NRW with the job of ensuring their safety. Between 2019 and 2023, £600,000 of taxpayers’ money was spent on two orphans – Cwm Clydach, Swansea, and Llyn Cae Conroy, Llanbrynmair, Powys.

Mr Irranca-Davies said all reservoir owners should be “aware of their respective responsibilities” – not just small landowners but also large companies such as Dŵr Cymru. But Ms Finch-Saunders believes the “phenomenal costs” involved will be too much for some and Cardiff should offer help. She pointed out that, between 2019 and 2021, NRW spent £6.4m on safety upgrades at just 10 reservoirs. “That’s averaging out at around £600,000 per reservoir,” she told the Senedd.

“Only £20,000 has been allocated to NRW’s reservoir regulation team for its work in relation to the private reservoirs. There isn’t a single penny of support for owners of private reservoirs, despite the costs that could be involved and the significant risk to whole communities. Wouldn’t it be wiser..... to take a more proactive approach, which sees the state and the private owners co-operate together?”

While the Welsh Government may be able to assist and advise, Mr Irranca-Davies said the onus lay with private landowners. “Let me make it very clea,” he said. “This cannot nor should not fall entirely on the taxpayer. If I owned a piece of land with a reservoir on it, grand or small, it is my liability within that.

“Where they don’t comply with their duties under the (Reservoirs) Act, NRW has a range of enforcement powers at its disposal, including undertaking necessary works to maintain the safe operation of the reservoirs, and seeking to recharge these costs. So, there are safeguards in place here.”

Since reservoirs legislation was introduced in Wales and England in 1930, no lives have been lost as a result of reservoir failures. Sign up for the North Wales Live newsletter sent twice daily to your inbox

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