October flood repairs, including urgent work on infrastructure at the mouth of the Clutha River, could cost the Otago Regional Council up to $2.54 million, a new report says.
A report to be presented to councillors today said staff were still assessing damage to council assets as a result of the storm that inundated parts of the province, causing landslips and surface flooding, at the beginning of October.
However, 30 council assets or sites the council was responsible for had been identified as priorities that required repairs.
Councillors will be asked today to authorise council chief executive Richard Saunders to spend up to $2.54m on the work outlined in the report, including up to $1m on a contract to Southroads Ltd to do urgent repair work at the Puerua Training Line at the mouth of the Koau branch of the Clutha River.
More than 200mm of rain fell at one council monitoring station over the three-day period and the highest rainfall totals in the coastal margin from Palmerston to the Catlins, and the coastal hills in Dunedin, Waitaki and Clutha, the report said.
On October 5, the council was asked to alleviate extensive farmland flooding, which it did by cutting the training line.
Following this though, over one night the cut expanded to form an open channel about 50m wide.
“Significant work is now required to reinstate the training line ensuring the continued function of both the drainage for the Puerua River, and to maintain the mouth of the Koau branch of the Clutha-Mata Au River,” the report said.
“In its current state Koau-Puerua training line is at risk of further damage from erosion from the Clutha-Mata Au or Puerua River.”
The estimated cost at present was about $750,000 to supply and place the rock fill and rip-rap, it said.
Culverts and site reinstatement works were yet to be estimated but were included within a $250,000 contingency value, it said.
Southroads were approached as they had done emergency works and flood repair works previously for the council.
Flood bank repairs at seven locations in the Lower Clutha area were expected to cost $735,000 and erosion repairs across the region were estimated to come in at $305,000.
The estimated cost of repairs from the October 2024 flood would make it the most costly flood since February 2020, which required about $4.6m of repairs, the report said.
Meanwhile, a Dunedin City Council spokeswoman said it remained too early to provide an estimated cost of the flood to city council infrastructure and it would likely be several months before the council could provide further details.
“Our transport, parks and recreation, and Three Waters teams and contractors are continuing to address ongoing jobs from the event.”
The council was working with other agencies on its response, the spokeswoman said.
