Tasman floods recovery expected to cost $50m, take two years

More than six months after back-to-back floods caused widespread damage across the Tasman District, the recovery is expected to cost the council $50 million and take up to two years to complete.

Record rainfall caused widespread damage across the district, described as the worst in 150 years, after it was hit by devastating floods twice in as many weeks during June and July.

It caused extensive damage to farms and rural properties, with land lost to swollen rivers, crops inundated with silt and fences washed away.

More than 60 roads were closed due to flooding, landslips and fallen trees. and hundreds of homes were assessed for damage. with 36 yellow-stickered and five red.

Nelson Tasman Emergency Management Group recovery manager Richard Kirby said the repair bill after the floods was estimated at $48m, with around three-quarters of that covered by insurance payouts or government contributions, leaving around $12m in costs to the council.

The total cost of damage to river infrastructure was between $23 and $25m, while the roading damage was just over $20m.

Kirby said the cost to private landowners was not known, but Insurance Council of New Zealand figures showed there were 2807 claims totalling $37.4m from the June floods in the South Island, bringing the total cost close to $100m.

A report tabled in Parliament in early December found local councils need to be doing more to prepare for flooding and to mitigate the risks it poses to communities.

The report, by the Office of the Auditor-General, looked specifically at the Tasman District. One of the weaknesses it identified was the council's understanding of the condition of its flood protection infrastructure and the lack of a regular schedule of inspections.

It made several recommendations, including that the council prepare a framework to prioritise the maintenance and capital work needed for its flood protection infrastructure, along with improvements to its asset management processes.

Years to rebuild river infrastructure

Many of the region's rivers reached record levels in the floods, with the Motueka River downstream of Tapawera and the Wai-iti River south of Belgrove, the worst-affected.

Kirby said the rivers team had done a stocktake of the river network and prioritised the critical areas that were susceptible in future floods. Around $6m had been spent on river work, so far.

"They've identified the areas that are less resilient and they're working their way through them on a priority basis so that should we have another [flood] event, the critical areas would have been fixed before next summer.

"Even though a lot of the areas we will be fixing up after next winter, but they're not considered at this point to be a major concern in terms of lack of resilience for future events."

He said some of that was stop bank work, but much of it was in-river work and rock shoring to stabilise banks in a bid to stop further erosion.

"I think at least it's probably heading up towards 18 months, maybe two years before we get on top of it and of course, that's hoping that we don't have another event over that period of time to undo what we're trying to do."

Kirby said the council had a "compromised database" of river assets and infrastructure, as highlighted in the auditor general's report, and it was working to improve its records for future monitoring, maintenance and insurance purposes.

"If you don't do that upfront planning and investment, then you end up with problems later and I think to a certain degree, we're in that space where we probably haven't done sufficient monitoring and planning in the past."

District-wide road repairs

Since the storms, Kirby said there had been 4500 roading jobs and there were now 1000 left to address, with close to 30 people out working on the roads each day.

The storms had caused several slips on State Highway 60 over the Tākaka Hill, which was down to a single lane in parts, with six sites badly damaged and in need of significant repairs.

New Zealand Transport Agency (NZTA) system manager for Nelson-Tasman Rob Service said extensive work was done to rebuild and strengthen sections of road, address erosion risks, improve drainage, and stabilise the ground. It would help to future-proof the sites against weather-related damage in the future.

Works were completed before Christmas, with the road reopened to two lanes.

Four roads across the district remain closed; Haycock Road, Quail Valley Road, Gannet Heights and Graham Valley South Branch Road.

The Graham Valley South Branch Road provides access to the Kahurangi National Park. A major section was undercut by the Graham River and the road has remained closed since.

The road is managed by the Department of Conservation (DOC), with support from the council.

DOC Motueka operations manager Chris Golding said work was underway to get the road open again as soon as possible to restore access to Flora car park, which is the gateway to Kahurangi National Park's most popular alpine walks including Wharepapa/Mt Arthur.

It was working on a repair plan, with work due to start in early 2026. The final cost was not yet known but it would be funded by Tasman District Council, DOC and NZTA.

"It's taken some time to develop an appropriate repair programme because the slips are significant and complicated. To repair them we will need to clear some slip debris which have changed the course of the river below the road, and to dig out sections of the road and fill it with stabilising material, which will need to be trucked in."

In the meantime, the road remained closed and people were asked not to cross it for their own safety.

The Tasman District Council said there were several homes on the other side of the slip site and residents were able to walk out while the road remained closed.

Ongoing impact on the rural community

Top of the South Rural Support Trust chair Richard Kempthorne said it had been a busy six months and many farmers still had recovery work to do.

The trust had spoken to 220 farmers, many who had land beside rivers and waterways and had been affected in various ways, with gravel, silt and debris washed up on farms, fences destroyed or they lost chunks of land to swollen rivers.

"It's still challenging, some people are still quite affected and struggling with it and others have done what they can do. Others are doing what they can do, but are generally stoic and are moving on.

"For a lot of them, there's been a lot of costs that they will then have to pay off over the next few years."

Kempthorne said Enhanced Task Force Green, a Ministry of Social Development initiative, had seen two teams of nine working for the last six months to clean up properties.

"Most of them are young people and they've been absolutely tremendous, they've got real great kudos from the people that they've helped."

He said some landowners had also struggled to know what work they were legitimately able to do to their properties in recovering from the floods, and what required consent, while others were grappling with the changes needed to mitigate against future severe weather

"For all the people living adjacent to the rivers, it's just knowing how to make sound decisions with the use of land/or assets going forward and sometimes that's quite hard to do because you may think, 'Oh gosh, I don't think I can keep doing what I have been doing.'

"Often with these issues, it does come back to how much private landowners are going to need to spend to recover properly and that can just be a very big challenge."

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