Nestled between the Caerneddau mountains and the Afon (River) Conwy, the small village of Dolgarrog in north Wales looks peaceful. But the huge hydro-electric pipes that run down the hillside are a constant reminder of the village’s history, and of how the same source of power that once brought prosperity also unleashed disaster.

On November 2 1925, the dam at Llyn Eigiau burst. A torrent of water and boulders thundered down the valley, sweeping through the northern part of Dolgarrog and destroying the small settlement of Porth Llŵyd. Sixteen people were killed.

One hundred years later, Dolgarrog’s story is not just one of tragedy. The village has become what its residents call a living memorial. It’s a place where disaster is not only remembered, but woven into the landscape, the law and the community’s sense of itself.

At 8pm on that night, the inhabitants of Dolgarrog felt the force of a catastrophic sequential engineering failure in the mountains above.

Two reservoirs, Llyn Eigiau and lower Coedty, supplied electricity to the local aluminium works, an industry that sustained the village. But the upper dam at Eigiau had been built on a foundation of glacial clay and boulders. After a dry summer, the clay had cracked. When autumn rains came, water seeped through. The dam wall gave way, unleashing a surge down the afon Porth Llŵyd.

This flood rapidly reached the lower Coedty dam, overwhelming its embankment. As the second dam failed, the water rushed like a massive tsunami wave down the steep gorge of afon Porth Llŵyd. Ripping out the hydro-electric pipeline, it created a deadly flow of water, debris and boulders that destroyed homes, and swept villagers into the afon Conwy.

From local tragedy to national protection

The Dolgarrog disaster was not the first dam failure in the UK, but it was the one that forced government action. Public outrage over the deaths of 16 villagers led directly to the Reservoirs (Safety Provisions) Act 1930, the first law in the UK to regulate dam safety.

For the first time, large reservoirs had to be inspected and supervised by qualified, independent engineers. This ended the era when private companies could self-regulate. It marked a major shift in how the UK governed risk and infrastructure.

The event was codified into national law and updated in 1975. It created an invisible, yet mandatory, safety structure that continues to protect people today.

If the law is an unseen memorial, the land around Dolgarrog is a visible one. The remnants of the Llyn Eigiau dam wall still stand, a stark reminder of the engineering flaws that caused the disaster.

Downstream toward the Coedty dam, the torn-up peat moorland is barely visible. But the afon Porth Llŵyd gorge still shows the impact of the powerful flood, constrained by its bedrock walls. As the flood waters thundered down the gorge, they shattered, split and tore at the bedrock walls, ripping huge boulders from their rest.

The boulders dumped at the gorge’s outlet, formed a huge fan of rock debris still visible at the roadside – a chilling, preserved record of the suffering.

That landscape tells a story, not just of destruction but of recovery. The village’s memorial walk, created in 2004 around the boulder field, traces the path of the flood and symbolises the community’s ability to reclaim the space. It is both a site of reflection and an everyday walking route. This is cultural resilience and proof that remembrance and daily life coexist.

Disasters are not just events of the past: shape how we individually and collectively experience places, politics and society. Dolgarrog’s residents are marking the centenary with a programme of events under the banner “Dolgarrog Past, Present and Future”. These include commissioned art, musical performances, history projects and a lantern parade – acts of remembrance that also look forward.

Lessons for today

The lessons of Dolgarrog are as urgent now as they were a century ago. In an age of climate change, when extreme rainfall and flood risks are rising, the need for strong safety standards and accountable infrastructure has never been greater.

The 1925 disaster shows why state oversight of private infrastructure is vital when public lives depend on it. It also offers a model of resilience, one that is legislative as well as communal.

A hundred years on, the memory of the 16 villagers who died is not only preserved in stone and ceremony, but in the law itself, and in the ongoing safety of every major reservoir across the UK. Dolgarrog remains a living memorial to both the dangers of neglect and the power of collective renewal.