Flood Lessons Save District From A Worse Fate In Latest Rain Event

Friday, 2 May 2025, 8:12 pm
Article: David Hill - Local Democracy Reporter

Torrential rain brought flooding, slips and road closures to parts of North Canterbury, but local leaders say they came out relatively unscathed.

There were reports of slips in the Lees Valley, behind Oxford, while rivers rose around Hamner Springs, closing a local campground.

But, local councils say recent investment in flood defences ensured the region was protected against the rain, including new pumps in Kaiapoi.

Waimakariri District Council chief executive Jeff Millward said the rainfall was similar to rain events in 2014 and 2021.

But the council has made significant investment in stormwater infrastructure over the last 10 years and established a specialist flood response team last year.

‘‘With these types of events we always have learnings,’’ Mr Millward said.

Hurunui Mayor Marie Black said the rainfall was significant, but not as severe as council staff first feared.

On Thursday, state of emergencies were declared in Selwyn district, Christchurch and Banks Peninsula as flooding and slips threatened homes, and Mr Millward said his council was close to joining them.

‘‘We definitely had a nervous first night on Wednesday and from then on we were watching river levels closely.’’

Unofficial figures indicate there was 236mm of rain at the Ashley Gorge in 48 hours, and between 100mm and 135mm at Rangiora, Woodend and Kaiapoi, Mr Millward said.

‘‘Some of those numbers are quite alarming. I think Christchurch is talking about this being one of the top five rain events and we weren’t too far off.

‘‘It all comes down to good preparation, but even with the best of preparation, with rainfall you never quite know where it’s going to fall.’’

Mr Millward had high praise for Environment Canterbury’s rivers team, which kept Waimakariri council staff up to date with river management information.

The council invested more than $20m on stormwater improvements in Kaiapoi, including $9m from central Government, following previous flood events.

In last year’s Long Term Plan, the council set aside funding to establish a specialist flood response team.

It led to staff proactively setting up pump stations in response to the heavy rain and having five civil defence teams in an overlapping roster to monitor the event.

‘‘There’s a lot that goes on behind the scenes that people don’t see - including planning for the worst, which could involve evacuating large portions of the district,’’ Waimakariri Mayor Dan Gordon said.

‘‘From my travels around the district it was clear the improvements and significant investment especially in the new pumps in Kaiapoi made the difference, as well as having pumps and sucker trucks on standby in other trouble spots.’’

Hurunui District Council chief executive Hamish Dobbie said there was some road damage, and several roads and fords remained closed.

Mrs Black said the impacts varied across the district, with rivers rising at Hanmer Springs, closing the Hanmer Reserve for camping, and there were high flows in the Waiau and Hurunui rivers.

She said there will be follow up work for staff with service requests and assessing damage.

‘‘These things are not without cost to the council, but we will work through it diligently and responsibly.’’

Both councils will continue to monitor the situation, with updates available on their respective websites and Facebook pages.

LDR is local body journalism co-funded by RNZ and NZ On Air.

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