Cyclone Gabrielle: Northland councils put $250m price tag on roading repairs after severe weather

An underslip on Kaiwaka-Mangawhai Rd, which is used as a Brynderwyn SH1 diversion route. Photo / Supplied / WSP

Te Tai Tokerau councils are warning $250 million is needed to sustainably fix ailing local roads as roading infrastructure damage spreads “like smallpox” across the region.

There have been more than 1770 live slips across Northland’s 5755km of local roads in the wake of Cyclone Gabrielle and seven other major weather events since July 2022.

Before Cyclone Gabrielle, more than 1000 slips were spread along 1110km of the most crucial local roads – averaging one slip per kilometre of road. A further 645 slips occurred when Cyclone Gabrielle hit and flash flooding in Mangawhai on February 24.

More than half of those additional slips were the more serious underslips – where foundation roading infrastructure under the road slips out from underneath the road. Eight of Northland’s local roads were reportedly still closed after the last two major weather events.

Northland Mayoral Forum chairman Vince Cocurullo said Cyclone Gabrielle further seriously exacerbated the roading infrastructure damage spreading across the region like smallpox.

“The current estimate to repair and improve Northland’s local roading network is $250 million. This funding is essential to provide Northland with a safer, more resilient local road network.”

More central government money was needed to fix the region’s damaged roads after what had been decades of underspending.

Cocurullo said the $250m was about providing a sustainable - but not gold-plated - fix for the region’s local roads.

He delivered the Northland Mayoral Forum message loud and clear to Minister of Local Government Kieran McAnulty on Monday via a livestream of a meeting between the region’s local government politicians in Whangārei.

Cocurullo also sent a new Northland Transportation Alliance report on the weather events’ compounding local roading effects to McAnulty and Minister of Transport Michael Wood as well as Te Tai Tokerau MP Kelvin Davis, Whangārei MP Dr Emily Henderson and Northland-based National MP Dr Shane Reti.

The eight major weather events - that include cyclones Gabrielle and Hale, and the deluge that shut State Highway 1 over the Mangamukas – brought $75 million in damage to the region’s local roads network in the first eight months of the current 2022/2023 financial year.

Before Cyclone Gabrielle, $23.7 million in roading damage had occurred mostly in the Far North ($18.4m) followed by Whangārei ($3.5m) and Kaipara ($1.8m). Cyclone Gabrielle added to that with an early $50m roading response and repair estimate (Kaipara $23m, Whangārei $20m and Far North $10m).

Cocurullo also noted the nearly $120m needed to bring the Kaipara and Whangārei roads used as diversions around the Brynderwyn Hills up to scratch as sustainable diversions. This included $52m for Paparoa-Oakleigh Rd and $10m for Cove Rd.

He said a further estimated $36.28m was required to repair just 10 per cent or 116 of Northland’s local road slips.

Cocurullo said slip and damage assessments were completed for only the most crucial 40 per cent of the region’s local roads.

Local roads were categorised and ranked including to what degree they served forestry, schools, marae, churches, quarries, residential areas and land use such as avocadoes or dairying - as well as how wide and how remote they were.

Underslips dominated the remaining closures on four of the five affected Whangārei District Council (WDC) roads – Finlayson Brook, Shoemaker, Waipū Caves roads and Memorial Dr on Parihaka. An overslip that had fallen onto Stuart Rd in Whangārei Heads was the fifth closure.

The damage to Shoemaker Rd, near Waipū, was caused by Cyclone Gabrielle. Photo / Michael Cunningham

Underslips had resulted in Tangowahine’s Avoca North Rd and Mahuta Gap Rd near Dargaville also Kaipara District Council (KDC) still being closed. Mangawhai’s Devich Rd was still closed because of bridge damage.

Cocurullo said a further 67 local roads were still down to a single lane (WDC 43, KDC 19 and FNDC five).

He said local road detour roads were getting increasingly damaged with SH1 Brynderwyns bypassing.

Regional Transport Committee chair Joe Carr said it was good to see the Government put funding towards some of the region’s earlier weather-damaged local road repairs but more was needed.

He said people hadn’t yet taken on board that the weather events battering the region since July last year were not aberrations of normal. They were part of a new normal the region had to lean into.

Carr said road funding needed to be at a level where extreme weather damage and normal scheduled roading maintenance could both be done.

There needed to be more investment in developing local skills and resources to build resilience into Northland’s roading network repairing rather than having to rely on large companies from outside the region doing the job, he said. Additionally, pre-emptive main route roading resilience work needed to be done via major investment.

Carr said fixing areas of poor stability before the road dropped away in an underslip was up to 30 times cheaper than doing so after the slip happened.

Work being done to address main route access such as through SH10′s Waipapa also meant addressing surrounding catchments, in the case of this location, investigation into an upstream Kerikeri River detention dam illustrated the point.

■ Local Democracy Reporting is Public Interest Journalism funded through NZ On Air