Flooding threat from dam sinkhole

The threat of heavy rainfall and flooding still looms for the Elsthorpe community as the Hawke's Bay Regional Council works to fix the damaged Makara Dam.

A sinkhole was found on the face of the flood detention dam on May 31. Without heavy rainfall the dam is empty and has no risk of failure, although the community remains susceptible to flooding.

The dam is one of five constructed in the 1980s. They were constructed to temporarily hold excess flood water in a ponding area. In normal weather the dam is empty, with in-flowing water exiting through a pipe in the face of the dam. During storms, the capacity of the pipe is exceeded and water builds up behind the dam.

Makara liaison committee member James Thomsen said the dam had been reduced in height by 60 per cent.

"The situation hasn't changed as far as I'm aware," he said. "There is still the same issues, and I believe that the dam has been reduced in height by 60 per cent.

"They [Hawke's Bay Regional Council] have done all they can to prevent any danger that they can foresee, and while the weather is good it won't be a problem. The concern is that we will get a water event in the next few months that causes major flooding."

It could be several months before the problem was solved, he said. "There is no quick fix unfortunately. They are telling me that there is no opportunity to repair it straight away. That would have to be done when the ground conditions allow heavy machinery to go in there and do the work.

"I think there is a great deal of concern. Just that there is nothing that we can do about it, and therefore we look forward to working with the regional council to remedy the situation."

A staff report was presented to the regional council yesterday to allow spending to solve the problem. The Makara Flood Control Scheme has slightly more than $200,000 in it, but expenditure was expected to exceed this.

Council staff have been working with Damwatch Services and Central Hawke's Bay District Council to address the problem, and is considering installing a water level recorder to warn properties downstream. They were also arranging a community meeting in the next few days.