Water expert challenges ESB to explain huge spillage from dam

FLOOD MANAGEMENT:AN EXPERT on flooding in Cork has challenged the ESB to state its protocols for discharging water from Inniscarra dam following the release of a huge volume of water last Thursday which swamped an extensive section of the western side of Cork city.

Prof Robert Devoy, who teaches courses on hydrology and physical geography at University College Cork, said it must have been clear to the ESB, given rainfall levels throughout the summer and early autumn, that water table levels were very high.

This would have reduced the absorptive capacity of the ground to cope with further heavy rainfall forecast for November.

“Given high levels of saturation and forecasts a month ago from Met Éireann and the British Met Service that November was going to be very wet, I would have been releasing water from Inniscarra as fast as I could for the three weeks before the flood,” he said.

Responding, ESB executive director of power generation Michael McNicholas told The Irish Times the company had been aware of the reduced absorptive capacity of the land and had been monitoring weather forecasts closely prior to the emergency situation.

“What happened was that on Monday 16th, our staff at Inniscarra looked at the Met Éireann forecasts and saw that there were significant volumes of rainfall forecast for the week and they recognised that they would have to have a significant level of spillage and issued a flood alert.

“We were spilling water at a rate of 150 cubic metres per second and we continued at that level right through until Wednesday 18th.

“Met Éireann was forecasting rainfall of 46 millimetres on Thursday but our records show that almost double that amount, 90 millimetres, fell in the Lee catchment. We were monitoring this throughout and at 11am on Thursday, we issued a serious flood warning to all emergency services.

“We began increasing our spilllage incrementally from 150 cubic metres per second at 11am up until 535 cubic metres per second which we reached at 11pm and we issued further flood warnings at 4pm to the emergency services and local radio stations.

By 6pm the company had issued a public service warning to the RTÉ newsroom, he said.

“By then, our staff had serious concerns for the overall integrity of the dam so we increased our spillage to 535 cubic metres per second to prevent a catastrophe which would have led to uncontrollable flooding given 800 cubic metres a second was entering the system. It was the sudden increase in rain on Thursday – double the amount that Met Éireann had forecast – that forced us to take the action,” Mr McNicholas added.