Dam alert triggers new evacuation (From Ilkley Gazette)

Dam alert triggers new evacuation

7:46pm Sunday 10th June 2012 in National News © Press Association 2013

Hundreds more residents have been evacuated from their homes - as others went home to begin clearing up after being flooded out on Saturday.

The new drama was just 20 miles from where flash floods brought havoc to communities in west Wales following heavy rainfall.

North Wales Police evacuated residents from the village of Pennal, near Machynlleth, Powys, following a breach in the dam of a quarry. Residents were taken to Machynlleth Leisure Centre and other temporary refuges.

Superintendent Andy Jenks-Gilbert said the evacuation was a precautionary measure. A crack had been found in a wall and a small amount of water had escaped.

Gwyn Jones, of North Wales Fire and Rescue Service, told the BBC that a member of the public had called about his concerns over a reservoir on his land. The decision to evacuate residents was based on the volume of water involved and the heightened risk from rain and debris coming down and making it an unstable structure, he said. The reservoir was not man-made, but formed when a derelict quarry with accumulated slate waste formed a barrier for the water, which had built up over the years.

"There has been a build up, causing stress to that slag heap, and that is what is causing us concern, as a service," he said. "We are awaiting a specialist hydro engineer to give us further details in relation to the future movement or stability of the slag heap itself. Based on that information we will be able to carry out our plan of action, either to set up pumps to relieve the pressure mechanically, or allow it to drain naturally."

North Wales Police said later that controlled release of the water had been undertaken and was continuing to reduce the water level. It was hoped that people would be able to return to their homes later this evening. It was estimated that about 100 households had been affected. Some 80% of residents had left their homes, some of whom had gone to the local leisure centre.

Mr Jones told the BBC: "Over the course of the day, we've been able to undertake two releases of water from the reservoir. We were closely monitoring the level of the river, and everything was satisfactory after those two releases. Subsequently, contractors and the landowner have created a permanent channel in the reservoir which is allowing the water to dissipate naturally and at a steady rate.

"Based on that information and survey from specialist pump operators on the scene, we were able to give the advice through North Wales Police that residents were able to return to their homes."

He said they had been dealing with about six million gallons of water. "The pressure on the reservoir was immense, so public safety was paramount. We have managed to avert a very serious situation."