Council denies dam to blame for flooding

8:28 am on 7 April 2017

Bay of Plenty Regional Council has denied the management of the dam above Edgecumbe led to flooding of the town.

Slip on road to Mathura Dam

A slip on the road to Matahina Dam Photo: RNZ / Sharon Brettkelly

Some local people have pointed the finger of blame at the Matahina Dam, upstream from Edgecumbe, saying it caused the deluge in the river which breached the flood wall.

Resident Graeme Bourk was 50 feet from the floodwall before it collapsed, and said the dam should have been spilled for at least a month to avoid the flooding.

He told Morning Report a similar event happened on the other side of town in 2004 and Trustpower, which operates the dam, gave assurances it would never happen again.

Former Whakatāne mayor Colin Holmes said Trustpower panicked and opened the dam too late and the council misjudged the peak volume of the water and when it should be released.

There had been under-investment in flood monitoring schemes since a previous major flood 13 years ago, so history had repeated itself, he said.

"Exactly what happened in 2004. Poor information, poor flood management protocols between the regional council and Trustpower. Result: disaster."

'We couldn't have done it any better'

But Roger Waugh, who is in charge of managing the floodwaters including control of the floodgates at the dam, told Morning Report the flow was lowered to the minimum level well before the event.

"We've used that dam to reduce the flood event that's come through Edgecumbe," he said.

Spilling from the dam had started on Monday.

"The dam was an asset in this event. It reduced the flow down through Edgecumbe by 100 cubic metres a second. That's 100,000 litres a second we reduced that flow of water.

Mr Waugh said the flood wall which failed had been there for decades, and went through the last flood event. It had failed very quickly, and they don't yet know why.

Whakatane district mayor Tony Bonne told Morning Report he'd heard concerns about the dam "from a couple of people".

"But I've also heard from other experts telling me what we could have done better with the concrete wall [along the Rangitāiki River] that collapsed.

He said he would be talking to the Prime Minister about it today.

"I'm sure there'll be some sort of investigation to make sure things have been done correctly."

"Everybody's got a firm view of what should have happened and all I can say is that we are going to get to the bottom of it."

Trustpower said it followed procedures correctly.

Chief executive Vince Hawksworth said the idea that anything could have been done differently was difficult to accept.

"Ultimately we absolutely followed the plan that's embedded in our resource consent and operated under instruction as we should do in that event."

Mr Hawksworth said Trustpower would participate fully and openly in any review into how the dam and flood procedures were managed.

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