Why the risk of another dam disaster is growing each year

Dam disasters of the 1920s made reservoirs safer - now the climate crisis is increasing risk again, suggest experts. Andrew Forgrave reports

- Andrew Forgrave

ONE hundred years ago, a catastrophic flood carrying gigantic boulders swept through part of a Conwy Valley village, destroying homes, a bridge and the local chapel.

Ten adults and six children lost their lives. The tragedy shocked Britain and King George V sent a message of condolence.

Yesterday, Dolgarrog remembered the disaster with a half-mile lantern parade and a commemoration service at its cenotaph. What happened there has lingered long in local memory and the lessons learned continue to influence reservoir safety today.

Three academics have looked back at the tragedy to assess whether more needs to be done to prevent a repeat as the climate changes.

Prof Jamie Woodward, professor of physical geography at Manchester University, concluded upland reservoirs like those above Dolgarrog will become particularly vulnerable to drought and flash flooding.

He was backed by Prof Jeff Warburton of Durham University and Prof Stephen Tooth of Aberystwyth University.

Prof Woodward said Dolgarrog was a profoundly human tragedy that was caused by the failure of two dams impounding the Eigiau and Coedty reservoirs in the Carneddau mountains. Following a wet October, the Eigiau breached and its outflow ran down to the Coedty, which overtopped before its dam failed catastrophically.

A tidal wave of some 1.7 million cubic metres was unleashed, gathering boulders as it rushed down a narrow gorge. In its path lay Dolgarrog, whose residents had no inkling of the "avalanche" about to hit them. Many more would have died if they had not been watching a film in the village theatre, which was on higher ground.

The reservoir failure was the second that year, following another at Skelmorlie, Scotland, in April 1925.