Nelson's long, sodden road to recovery

From The Detail, 5:00 am on 9 December 2022

Nelson was hammered by a massive storm back in August, bringing down landslides across the city and forcing people out of their homes. The Detail looks at the progress made in repairing the damage - and what the city's doing to prepare for the next one.

Behind a wire fence there is a small red house with an overgrown lawn around it. The left side of the house has been hit by a landslide. Behind the house are tall trees.

A red-stickered house in Tāhunanui. Photo: Sharon Brettkelly

It's four months since torrential rain drenched Nelson, forcing hundreds of people from their homes and bringing down slips across the city.

The main road to Blenheim, State Highway 6, is still closed and dozens of properties remain uninhabitable. 

On Rocks Road is a well-known red cottage. It sits at the bottom of the hill and looks across to Tāhunanui Beach.

It's surrounded by debris from a massive slip.

"You can see the mud visible in the house on the ranchslider, knee-height," RNZ's Samantha Gee explains to The Detail.

"I've seen photos of the family who were renting it at the time, standing in there with really thick mud and unable to even salvage a lot of their belongings."

A hillside has collapsed into the back of someone's yard. A slip of loose earth wrapped in wire is slumped over a wooden fence. There is a neighbour's house and fence in the background. Above is a blue sky.

A slip caused by August's flooding. Photo: Sharon Brettkelly

On the slope above the house, Gee says there are little white pegs in the slip, which are being used by geotechnical engineers as markers, to keep track of how the land is moving.

"It's an active landslide, it's moving all the time by all accounts, but rain events speed up the movement in different areas," she says.

This area is known as the Tāhunanui slump and is the largest urban landslide in the country.

"It's almost a miracle really that there weren't houses that slipped down in this event or lives lost or injury, because there has been a lot of land movement," Gee says.

"They say the slump spans 26 hectares across this hillside, 700 metres wide, includes about 120 houses and in this most recent rain, 50 houses in this slump zone were affected."

Many were red- or yellow-stickered, others had problems with utilities, like water and sewage connections.

While August's rain event affected a wider area of the South Island, in Nelson alone there were 1200 insurance claims amounting to $22 million - though Gee says that figure is expected to increase as more damage is assessed.

"For many people, it's dominating their lives, dealing with insurance or navigating the process for remediating their land," she says.

"I think a lot of people are learning things that they have never had to know about, trying to make sense of what it means for them, what it means for their future, whether they want to stay living where they are or whether they want to move elsewhere."

Nelson mayor Nick Smith - who has a PhD in landslides - is frank about the remediation prospects for some slip-hit areas of Nelson.

The lounge of an abandoned house. There is green grass and weeds growing on the brown carpet. There is no furniture, but a few dumped items and cardboard boxes. The lawn outside is overgrown.

An abandoned house. Photo: Sharon Brettkelly

"There are going to be some of those landslides where the cost of their repair and making them safe could be done theoretically, but in cost terms is too much," he says.

The repair bill for the Nelson City Council is estimated between $40 million and $60m.

Smith says insurance will cover some of that; he's also had discussions with central government about whether it would stump up some money.

"I still don't want to mislead ratepayers into the fact that the council and they are ultimately going to take a big hit from those August storms and landslides."

When you add up the damage to council infrastructure, private property and government-funded infrastructure, like State Highway 6, Smith reckons the total cost of the storm will be pushing close to $200m.

"The other part we just need to be quite open about is that the process of assessing the geotechnical risk from each of these landslides and then working out where it's economic, and where it's not, is going to be an exercise that is going to take us a good 12 to 18 months," Smith says.

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