MORE than £5 million is needed to improve St Asaph’s 50-year-old flood defences to protect the city from being swamped again.
Denbighshire Council has published its first report investigating the floods from November 2012, which hit about 500 properties at 12 locations from Rhuddlan to Glyndyfrdwy.
This concludes that the flood defences built 50 years ago were overwhelmed.
“The current level of protection is insufficien. It needs to be brought up to a better standard," said Mohammed Mehmet, chief executive of Denbighshire Council.
“The defences were built in the 1960s. This does not imply they were not good enough at that time but for today’s standard it’s not good enough.
“Right now we are not happy with what is there.”
The main sources of flooding were the River Elwy, River Clwyd and River Ystrad which rose to record levels because of “heavy prolonged rainfall”on saturated ground, rivers overtopping their banks and blocked culverts.
Rebecca Maxwell, corporate director economic and community ambition said:
“The investigation shows the level of help the flood defence offers is lower than originally thought.
“The key findings of the investigation is that there is more to be done in St Asaph for protection.”
Natural Resources Wales is working with Denbighshire County Council to consider how to reduce the risk of flooding which could cost in excess of £5 million. The report will go in front of the full council on Tuesday, July 9 for approval.
Councillor David Smith, cabinet lead member for environment, said: “We put the people before trying to find out why it happened.
“It has been a success and residents have said that themselves, we have helped them get through it.”
A drop-in session will be held at Ysgol Esgob Morgan in St Asaph on Saturday, July 13 to allow residents to ask for more details about the investigation.
The flood report released on Monday said the investigation has raised questions concerning the hydrology of the River Clwyd.
The investigation focused on 11 areas which were affected by the floods. St Asaph - caused by overtopping of River Elwy affecting 320 homes and 70 caravans.
Lower Denbigh Road, South of St Asaph - caused by River Elwy affecting up to seven properties and 14 homes ‘a near miss’.
Rhuddlan (including Sarn Lane) - Marsh Road and Station Road - caused by River Elwy affecting 10 properties. Isolated sections of the River Clwyd flood defences were also overtopped upstream of Rhuddlan.
Denbigh, Brookhouse - caused by River Ystrad overtopping its banks affecting seven homes and one commercial property.
Llanynys - caused by River Clwyd affecting three properties.
Gellifor - caused by water entering a culverted watercourse with insufficient capacity affecting one property.
Ruthin, Park Place, Mwrog Street and Maes Ffynnon - caused by River Clwyd overtopping its defences at Cae Ddol and caused backing up in Mwrog Street culvert, affecting two properties.
Llanbedr DC - caused by exceeded capacity of a watercourse at Lon Cae Glas combined with culvert blockages affecting one property.
Loggerheads - caused by River Alyn overtopped defences.
Corwen, Green Lane - caused by high levels in the River Dee which overtopped its banks.
Glyndyfrdwy - caused by high volumes of surface water flow from a private land affecting two properties.