The cost of fixing storm damage inflicted on Whangārei district roads earlier this year has risen to more than $23 million - of which almost $11m has been spent clearing one giant landslide.
By Peter de Graaf for RNZ
The almost week-long January storm cut off coastal settlements at Ōakura and Whangaruru, swept away a bridge approach, damaged dozens of homes and destroyed others, and triggered a huge number of slips on the coastal road between Whangārei and Russell.
One section of road at Helena Bay Hill was only re-opened on Friday, after an eight-month effort to remove almost 100,000 cubic metres of soil, boulders and trees.
Further storms in March and April added more damage.
A report prepared for Whangārei District Council said the initial estimate for repairing storm-damaged roads was $16.5m, but that had now increased to $23.2m.
The report, by transportation manager Greg Monteith, sought councillors' approval for the extra $6.7m.
The NZ Transport Agency was expected to contribute $16m, leaving Whangārei ratepayers to pick up the remaining $7.2m.
The $23.2m total included $10.9m for emergency works at the massive Helena Bay Hill slip on Russell Road, the main connection between Whangārei and coastal communities at Ōakura and Whangaruru.
The council previously described the slip repair as one of the biggest and most complex projects it had ever undertaken.
About 93,000 cubic metres of soil, boulders and downed trees had to removed - reduced from the initial estimate of 110,000 cubic metres - and the 35m-high slip face had to be stabilised.
The cost of fixing the slip had previously been put at $7.5m.
The council would fund its share of the extra costs by borrowing, to avoid major delays or cuts to existing roading projects.
The report stated the original cost estimate for the Helena Bay Hill slip was based on a completion date of mid-2026.
Since then, however, persistent wet weather, difficult ground conditions, giant basalt boulders, fill site constraints and further slip movement had delayed work and increased costs.
Some boulders were so big, they could not be broken up, even with a 50-tonne breaker, and instead required blasting or a specialist rock-breaking crew.
The report stated there had also been delays due to health and safety issues, such as near-misses involving trucks and local residents, and unauthorised entry into exclusion areas.
Once the slip had settled, which was expected to take about a year, more funding would be needed to repair the road below the slip and along the 2km route to the clean-fill site.
The estimated road rehabilitation cost was $2.3m.
During the road closure, the Whangārei District Council operated a convoy, via steep, narrow and unsealed Kaiikanui Road, to allow continued access from the south.
Piloted convoys left every 35-40 minutes from 6.30am to 6.30pm, seven days a week.
The cost of operating the Kaiikanui Road detour was put at $2.1m.
According to claims recorded by the Insurance Council, the total nationwide cost of the January storm, was $75.9m.
More than 5000 claims were lodged including $54.5m for damage to homes, $13.7m to commercial property and $4.6m for vehicles.
According to the Insurance Council, the most costly event of the past decade in terms of insurance claims was the 2023 Anniversary Weekend storm, which totalled $1.98 billion nationwide.
About a week later, Cyclone Gabrielle cost $1.85b.
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