28 Apr 2017

Edgecumbe flood data to be used in natural hazards study

7:00 am on 28 April 2017

Scientists are heading to Edgecumbe next week to gather data they hope will help protect other communities in New Zealand and around the world from flood devastation.

Houses on College Road, opposite the stopbank wall on the river Rangataiki that breached and flooded the majority of the town causing the evacuation of 1600 residents.  Thursday 6 April 2017

Houses on College Road, Edgecumbe, near the breach in the Rangataiki River stopbank. Photo: RNZ/ Brad White

The Rangitaiki River burst its banks earlier this month and swept through the town, leaving most of it flooded and many homes unable to be repaired.

NIWA hazard and risk researcher Kate Crowley said such a big stopbank breach was relatively rare in New Zealand and they want to find out all they can from it.

A small team of GNS and NIWA scientists would look at the depth and velocity of the water that entered the town and its impact on buildings and infrastructure.

"That's really important because ... we don't often get the chance to look at what happens when buildings are exposed to that sort of level of flooding and that speed of water."

The data will be added to information gathered from previous floods, including major ones in Whanganui and Dunedin in the past two years, as well as wind storms.

Ms Crowley said that data was already being used in Samoa and Vanuatu and could be used in other countries to better understand natural hazards and prepare for similar events.

"The more events that we can go out and survey afterwards, the better our information is going to be and the more complete the picture that we have is going to be for the nation."

Matipo Place resident Shane Lowe, whose home was very badly damaged, said he would be happy to help with something that could assist the town.

The water reached 1.2m in his shed, 70cm in his home, left a layer of silt on his floor and swept away his fence, outdoor furniture and garage roller doors.

Despite the damage he said he felt lucky he and his family were safe, because it was clear the water had been very powerful.

The team would also look at flood warnings in Edgecumbe and how people reacted.

There was criticism from some residents that there was not enough warning - or that the risk from the river was overlooked.

Mayor Tony Bonne said it was useful to get plenty of data, but he worried there would be a duplication with an inquiry already being carried out by the Bay of Plenty Regional Council.

"In some ways, asking the same questions is maybe counterproductive.

"Everybody wants the data, everybody needs the data for the future but we do need it coordinated," Mr Bonne said

The scientists would be going door to door in certain streets next week but said they would not enter any properties without the owners' permission.