Engineers to tackle flooding in Waimakariri

A team of engineers is being assembled by the Waimakariri District Council to find solutions for the district's flooding problems.

Council utilities and roading manager Gerard Cleary said groundwater levels in places like Ohoka and Mandeville were at the highest they had been since 1978.

The saturated ground contributed to widespread flooding across Waimakariri on Tuesday, leading to flooded homes, closed schools, damaged roads and the evacuation of a Rangiora rest home.

Groundwater levels were expected to remain high throughout winter, putting the district at high risk of further flooding during any heavy rainfall events, Cleary said.

"We are taking it very seriously."

The council had pulled staff off other projects to look at immediate solutions for easing the district's flooding problems. Specialist engineers were also being brought in to come up with ideas.

Although most of the flooding had now receded, some residents were still having issues with their septic tanks and the council had put portable toilets in the Mandeville area.

Sewage plants had also been under pressure, forcing the council to discharge some of the excess water from the Rangiora plant into the Southbrook Stream.

Excess water had also been discharged from the Mandeville plant into sucker trucks and from the Oxford plant into a contained pit on-site.

"There's nothing we can do about that. There's just so much water," Cleary said.

South-west Kaiapoi was another "high priority" area for the council, with some properties having been flooded multiple times this year.

"That's a difficult one - it's a very low-lying area and to get a permanent solution in there would involve quite significant work and it's the kind of work that will take some time and is quite expensive."

The council was also busy repairing potholes and damage to road surfaces from Tuesday's flooding.

"We suffered a lot of damage to our roads. They'll be trying to patch that up as quickly as possible and will go back in the coming weeks to fix it up properly," Cleary said.

The Ashley Bridge, on Cones Rd, would remain closed for at least two more days pending further inspection of the piles, while the Jacksons Rd bridge, near Ohoka School, would be closed for at least several weeks after one of the abutments was washed away.

The bridge, which crossed the Ohoka Stream, was open to foot traffic only as the council sought expert advice on how to fix it.

"It's quite a major job. We'll potentially have to rebuild the entire bridge," Cleary said.

Ohoka School principal Kym Wells said the bridge closure was causing traffic disruption, with parents and caregivers having to detour through Tram Rd to get to the school's entrance.

The school had to close on Wednesday because damage to the bridge had also damaged the school's water supply.

"We have been affected in other weather incidents because we have some issues with infrastructure at the moment . . . but surprisingly we didn't have those issues this time," Wells said.

Meanwhile, 21 elderly residents evacuated from Rangiora's Bainlea House when the facility was flooded on Tuesday have settled into temporary accommodation.

Canterbury District Health Board acting chief executive Mary Gordon said the board was working with the rest home's management to check on the welfare of the residents and keep families updated.

"We understand the owners have made arrangements for a building assessment early next week, after which we hope to know more about how much work is required and the time frame for completing it," she said.

The Press