Denbighshire floods: Culvert blamed for homes damage
Blocked culverts have been largely blamed for devastating flooding which affected 122 homes on a Denbighshire estate last year.
Independent investigators said screens around the culverts on Ruthin's Glasdir estate were poorly designed and did not comply with recognised standards.
They were not capable of being safely cleared in an emergency, the Denbighshire council report said.
The council was not blamed but it said lessons must be learnt.
The homes on the Glasdir estate were hit by an overflowing River Clwyd after heavy rain last November.
Hundreds of homes in nearby St Asaph were also flooded when the River Elwy burst its banks.
People living on the Glasdir estate said they had been told that flood defences meant there was only a one-in-1,000-year chance of their homes being hit.
The report said the flooding was an "extreme" weather event.
Independent investigators had gathered evidence of why the river flooded, whether it could happen again and what action should be taken in future.
The report said blocked culverts on the estate had screens designed to stop people entering them but the screens were blocked, largely by vegetation.
"The screens were also of poor design, not complying with any recognised standard and were not capable of being safely cleared in an emergency," said the report.
The screens have since been removed and will not be replaced.
In a media briefing, council chief executive Mohammed Mehmet said: "There are lots of lessons for us certainly. There are lots of lessons and there are lots of things that could have been done better."
"I don't think you can say 'yes, because it was blocked it was the council's responsibility'," he added.
The council admitted it had no maintenance records relating to when the culverts were unblocked and said that would be one of the lessons learned.
Report author Dr Jean Venables said that "in most cases these things happen during the course of the flood".
The report said that "blockage of the culverts played a significant part in causing the flood water to flow over the bund (or embankment)" which was also too low.
It added: "Although blockage was mentioned in previous reports there is no evidence that work was done to assess its impact.
"It is only recently that a Welsh government survey has revealed 60% of flooding incidents on ordinary water courses were caused by blockages."
Mr Mehmet said the council would ask its members to fully endorse recommendations made in the report which include:
- Raising the bunds "as soon as possible" by as much as 1.1m in some areas
- Regular checks of the defences
- A network of flood wardens to monitor flood plains and culverts
- Exploring the possibility of a line of posts around the culverts' entrances to catch large debris and vegetation
The report said the bunds should be permanently raised as soon as possible, but that a temporary line of sandbags should be considered as an interim measure.
The council has also instructed a "risk register" of culverts to be drawn up and for inspections to take place on a regular basis.
Concluding the report Dr Venables said: "Hindsight is a wonderful thing but we cannot see any evidence that the decisions taken at the time were anything other than reasonable."
However, she added things would be done differently now.
Glasdir Residents' Association said it was "grateful" to the investigators for providing a solution.
However it said in a statement that residents "cannot forget the devastating impact that the flood had on our community".
The association added: "After a lengthy wait for long anticipated answers to questions of causation we have now been provided with a report which raises more questions than it answers.
"Accountability has been clearly avoided at every turn."
Ian Smith, managing director of Taylor Wimpey North West, which built the Glasdir estate, said: "It has always been Taylor Wimpey's intention to play its part in restoring confidence in the Glasdir development and we will work closely with the council and other agencies involved so that appropriate practical solutions can be implemented."
He added: "We remain committed to establishing conditions which will allow house sales on the site to resume so that construction activities can recommence, with the aim of completing the development of all 178 properties at Glasdir as originally planned."
In its own report, the Environment Agency - now Natural Resources Wales (NRW) - also blamed blocked culverts for the problem.