Some Kaipara road slips from February storms could take three years to fix

This slip on Peeblebrooke Rd, Mangawhai, was repaired in July, but many more slips in the Kaipara caused by severe weather events might not be fixed before mid-2024.

More than half of the 71 slips still impacting Kaipara roads in the wake of multiple severe weather events that hit Northland earlier this year should be repaired by the middle of next year but some may take up to three years to fix.

Kaipara District Council general manager for infrastructure Anin Nama said the council had already repaired 245 of the 300 slips caused by back-to-back storms and cyclones since February.

That included Cyclone Gabrielle in February, which brought record levels of rainfall and devastated parts of the North Island, and the localised damage from the February 24 Mangawhai significant rainfall event.

Of the 330 slips on the Kaipara roading network, 71 of the most serious and complex required detailed inspections by engineers to confirm repair options. These investigations had been hampered by ongoing instability of the slips caused by continued wet weather.

Last week, the council finalised its formal emergency works site assessment and confirmed that repairs to 43 Kaipara sites should be completed this financial year. The work will reinstate roads to pre-event conditions and were each estimated to cost $100,000 or less.

The February 21 to 28 storm caused widespread flooding and damage around Mangawhai, with some slips caused by the storm still to be repaired. Photo / Shane Wiski Whitmore

“The remaining 28 of the Kaipara’s 71 slip sites are the most complex, requiring specialised design and will cost over $100,000 each. These repairs will require formal procurement processes before contracts can be let. Some of these repairs could take up to three years to complete,” Nama said.

As well, some of the initial works would be revisited so the roads could be repaired to standard.

“With ongoing wet weather, and the need to work quickly, we’ve had to make some temporary repairs. We’re going back over those sites to restore them to their previous condition,” Nama said.

“We’re now prioritising a couple of key sites to improve access before the busy Christmas period. We’ve already started work to restore the Devich Rd bridge and we’re planning to open Mangawhai Rd up to two-way traffic as a temporary measure by Christmas.”

Kaipara Mayor Craig Jepson acknowledged the frustration felt by many residents who, for several months, have had to negotiate damaged roads, some of which had been reduced to one lane.

“The level of damage done over two weeks in February would normally take five years under normal conditions. We’ve completed over $11 million of an estimated $28 million of works attributed to the 2023 events. I want to thank the teams who have made huge progress to restore the network,” Jepson said.

“At the same time, they are continuing with general road maintenance planned for the summer construction season. This includes repairs to potholes, grading, trimming trees and improving drainage. Slips that existed before major weather events will be included in this work.”

A list of the slips caused by the weather events and their current status is available on Kaipara.govt.nz/road-repairs. This information will be updated as slips are scheduled for repair.

*An earlier version of this story incorrectly said more than half of the 71 slips may not be repaired by next year. We apologise for this error.