Nelson City Council has offered to buy out 10 homes threatened by slip-prone land in Brook Street at a cost of more than $5 million.
The council is currently discussing buyouts with property owners, after the slip risk from council-owned land, which began during last August's heavy rain, is higher than previously thought.
Nelson Mayor Nick Smith said the atmospheric river in August 2022 caused 18 slips on council land, that damaged 33 private homes. Two of those have already been bought out by the council.
Of those slips, three were in The Brook and the council planned to remediate them as part of a $17.3 million package approved in May.
But further geotechnical inspections showed remediation was no longer appropriate, as further rain this year meant the slips had become more widespread and unstable, posing a risk to 10 nearby properties.
Council said purchasing the affected properties had a lower net cost and risk than any other option.
But as the properties not been red or yellow stickered, Smith said residents were not aware of the risk and the offer of a buyout had come as a surprise.
While the council was not legally required to buy the properties, he said it was the prudent thing to do, given the council was liable as the land owner.
"We are part of this community, we want to do the right thing and that is why we want to work with these individual property owners, try and fairly compensate them for their properties but also make sure that we are keeping them safe and increasing the resilience of the Nelson community to the increased frequency that we are likely to see in these sorts of storm events."
All 10 property owners had been notified and the council was beginning to enter into negotiations. The estimated cost to buy out the 10 properties is about $5.6m in total.
The buyouts will be funded by the $17.3m that had already been approved in the council's annual plan for slip remediation.
The details of individual negotiations are confidential, with council offering to pay for an independent registered to carry out valuations for each property (based on the market before August 2022).
The buyout of these 10 homes is in addition to the potential buyout of up to 14 homes that were damaged by slips from private property during August 2022, which is subject to public consultation.
Smith said the situation not only came at a significant cost but was incredibly challenging and difficult for councils and communities to navigate.
He said there was no set timeframe for the buyouts, but another severe rainfall event could hasten the process.
In the case of a severe weather event, council would work with the landowners to consider an appropriate trigger for them to vacate their properties.
"This is hugely traumatising for these families being effectively told that their properties cannot be protected and cannot be lived in long term."
These properties differ from those that have been red or yellow stickered, with some homeowners still waiting to see if they are eligible for a cost-sharing buyout offer, put forward by the government.
Last month, the council agreed to publicly consult through its Long Term Plan on whether to buy out up to 14 properties damaged by slips that had originated on private land.
It came after a $12.3m support package was offered by the government to help with the recovery from the August 2022 floods, with $6m earmarked for property buyouts in a 50/50 cost-sharing deal with the council.
Those homeowners will have to wait until after public consultation is done next year to find out if they will be offered a buyout.
Smith said geotechnical assessments, engineering and design were still being done on the remaining 15 slips that had occurred on council land, with decisions yet to be made about whether the slips could be remediated, or there would be further buyouts.
"It is just the nature of the beast with these landslides that is the nightmare component of the clean up from the August 2022 event, that this is a moving feast and I have got no doubt there will be further changes as we work through over the next three or four years, resolutions to each of these big landslides."
Deputy mayor Rohan O'Neill-Stevens said the council had increased its monitoring of ground conditions on council land since the August weather event, which enabled more accurate risk assessments.
"It should be stressed that this is a specific response to a specific situation and should not be seen as an indication of what might happen in future weather events."
O'Neill-Stevens said there was a clear need for a national conversation on how the fallout from severe weather events was paid for.
*Due to incorrect information supplied by council, an earlier version of this article stated the buyouts were likely to cost $8m, but the correct estimate is $5.6m. It also stated the buyouts would be paid for by ratepayer funds and government funding - but they will be funded by $17.3m already approved in the Nelson City Council's annual plan for slip remediation. The 10 homes mentioned are additional to the 14 red or yellow stickered properties damaged by slips from private land that being considered for a buyout as part of a cost sharing package between council and government.