After the flood ebbs, repairs bank up

The view of the Whanganui River from Durie Hill lift tower yesterday morning. PHOTO/BEVAN CONLEY 161013WCBRC03

The state of emergency in Wanganui was lifted yesterday afternoon and now focus turns to repairing stopbanks damaged by floodwaters from the Whanganui River.

The state of emergency declaration was made on Tuesday afternoon and before nightfall about 120 residents from Anzac Pde in Wanganui East were evacuated.

And then in the early hours of yesterday, police and Red Cross staff were door-knocking again, this time upstream of the Dublin St Bridge when floodwater breached stopbanks near Boydfield St.

A total of 139 locals were affected. Twenty-five of them were housed by Civil Defence emergency services with the others finding temporary homes.

Cordons that had been in place from Tuesday night were lifted late yesterday afternoon and residents allowed to return to their homes. Building and environmental health teams have checked the properties to make sure they are safe to return to. Some property owners received help from the Fire Service to pump water from garages and lime is being applied under a number of affected homes.

But as the flood receded Wanganui District Council and Horizons Regional Council engineers focussed their attention on stopbanks battered by the floodwaters.

District council chief executive Kevin Ross said major concerns about the state of the banks had to be addressed.

As soon as the water levels dropped enough, Mr Ross said work would begin in reinstating the damaged sections of those stopbanks near the motor boat club and downstream around Kowhai Park.

He said the worry was that flood waters stayed at a high level for a long period which saturated the stopbanks.

"In some places water has oozed through the banks and some have slumped so those areas need to be taken care of immediately. As the flood waters drop we can get in there."

Horizons has lodged a resource consent to upgrade the stopbanks to a standard to withstand a 50 year flood. In their current form they fall well short of that level of protection.

The floodwater peaked at the 8.2m mark on the town bridge and it stayed at that level for a long period.

"As the river drops it puts pressure on those very wet stopbanks. We can see water oozing and bubbling at some points so when the river water is moving on the outgoing tide, and at speed, there's a risk those stopbanks could disintegrate," Mr Ross said.

"While the water level's high it more or less holds those banks in place but if it drops on an out-going tide it could literally suck those banks out. That's why we've kept the cordons in place until the water level drops."

He said there had also been some questions asked about the need to evacuate residents.

"Clearly in our view it was the right thing to do.

"All indications were the water was going to go over the stopbanks and the level at Pipiriki indicated to us the banks would be breached," he said.