Streams overwhelmed by deluge caused flooding

Sudden torrential rainfall into small streams was the cause of the massive flood damage in parts of Cork City and county.

According to the most senior engineer in Cork County Council, the areas of Douglas, Clonakilty and Glanmire all have small streams that couldn’t contain the rate and quantity of water in them on Wednesday night.

“Each of these areas had a small stream with a small and steep surrounding catchment area that couldn’t contain the rain. If you look at Douglas, we had just put a quality-approved culvert in by the Ballybrack stream and this was designed for a one- in-1,000-year flooding event. Yet, the rate of rainfall last night was 30%-40% greater than a one in 1,000 year event,” Noel O’Keeffe said.

Mr O’Keefe denied local rumours that the new culvert in Douglas was to blame for the five feet of water that destroyed businesses in the village. He said it was bigger and of higher design standard than the previous culvert, including a trash screen to protect against blockage. In the early hours of yesterday morning that trash screen couldn’t be kept clear.

“We checked the trash screen at 1.10am last night and it was fine. There was no debris blocking it. Twenty minutes later, it was blocked by gas bottles, concrete blocks, tyres and mud that had been carried by the sea of water,” he said.

Cork City’s Lord Mayor has admitted the city council failed to give timely and effective warning to homes and businesses of the flash floods that devastated both city and county yesterday.

Cork County Council, meanwhile, said it had sent staff door-to-door in Clonakilty at 1.30am, well before the floods struck the town.

More than 10 hours before disaster struck, Met Éireann issued an alert to both Cork City and county councils that rainfall of up to 70mm could be expected in certain areas. It did not specify which areas were likely to be affected.

Despite the devastation of 2009, when floods caused hundreds of millions of euro in damage, the city council did not pass on the Met Éireann warning to home owners in low-lying or vulnerable areas, confining the alert to about 60 traders signed up to a weather alert email list organised by the Cork Business Association.

Families and businesses in the city were mostly caught unawares with hundreds of residents trapped in their homes in the areas affected. Many houses had to be evacuated.