Clearing the way for future resilience in the roading network

BY SAM MORTON

WHEN A NATIONAL STATE OF EMERGENCY was declared on Tuesday 14 February due to Cyclone Gabrielle, more than 30 sections of state highway were completely closed to traffic, impacting a significant proportion of the roading network serving Northland, Auckland, Coromandel, Manawatu, the Central Plateau, Gisborne and Hawkes Bay. Several months on, it’s clear just exactly how much Waka Kotahi NZ Transport Agency (Waka Kotahi) and local councils are facing as they look to restore the damage and upgrade infrastructure.

In recent months, a myriad of treacherous weather has caused no end of problems in the upper North Island, with the damage from Cyclone Gabrielle, the Auckland

Anniversary floods and prior to that, ex-Cyclone Hale decimating key access routes and transport networks.

In the days and weeks that followed Cyclone Gabrielle, Waka Kotahi's immediate priority centred on reopening emergency access and lifelines to isolated communities, with multiple roading crews, contractors and bridge engineers working hard to get roads back open within a matter of hours.

Commenting on the extensive work that lies ahead, Waka Kotahi Hawkes Bay/Taira - whiti Regional Manager of Maintenance and Operations Jaclyn Hankin says that while many roads have now reopened, there were still several major routes yet to be reinstated.

“Initially, access was severely restricted on state highways and local roads (non-state highways managed by councils) across Hawkes Bay and Taira - whiti, with roads affected to varying degrees throughout the region,” Mrs Hankin says.

“In Taira - whiti, there were approximately 45 damaged sites on SH2 north of Wairoa and approximately 90 sites on SH35, while in Hawkes Bay, the number was 32 sites on SH5 and 98 between Bayview and Wairoa on SH2.”

Since the cyclone, work has been carried out to reopen SH35 north of Gisborne, SH5 Napier- Taupo - and SH2 between Wairoa and Napier – all proving to be important access roads in and out of the area.

Elsewhere, it was a similar situation for neighbouring regions such as Auckland, Northland and the Coromandel, with the scope of the recovery and rebuild becoming more apparent each day.

More than 200 slip events were recorded on the Coromandel and East Waikato highways in January and February alone, with more than 50 of them considered significant slips. Approximately 50 sites are still being monitored around the Coromandel - some that already have designs in place for permanent repairs, while others are being prioritised for drainage repairs, overslip and underslip stabilisation, or major vegetation clean-up.

Waka Kotahi System Manager Cara Lauder says the biggest impacts were felt on the coastal highways out to Raglan and Kawhia, and in particular Coromandel, with the close of SH25A, causing major disruption to the lives of many.

“While SH25A is closed, [Waka Kotahi] is acutely aware of the sacrifices locals, businesses and communities are having to make. The inaccessibility, extra travel time, increased travel costs, access to healthcare, impacts to freight, businesses, tourism and general day-to-day life are front of mind for everyone working on these projects,” Mrs Lauder said.

“A bridge will be built to reconnect this route at a cost of $30 to 40 million, and is expected to take between 12-14 months to build, with work expected to start in June 2023.”

Other repair projects in the region have included SH23 (between Whatawhata and Raglan), with a geosynthetic reinforced retaining wall built and SH31 (Kawhia Road) - with total project costs pushing almost $5 million.

Echoing the sentiments of her colleagues, Waka Kotahi Auckland/North Regional Manager of Maintenance and Operations Jacqui Hori-Hoult says roading crews had been onsite clearing slips, debris and fallen trees and reopening the roads as soon as practical.

“SH1 Brynderwyn Hills suffered significant damage with severe underslips and overslips, and after a number of temporary closures between February and April to repair these slips and install drainage to help to futureproof stormwater resilience, the road was reopened in both directions on 1 May,” Mrs Hori-Hoult says.

“Other roads that were impacted included SH1 at Dome Valley, SH12 and SH16.”

Currently, Waka Kotahi is in the throes of completing plans for future infrastructure resilience, working with key stakeholders on a strategic approach to determine the next steps. This strategic approach will identify options for recovery works in the short-, medium- and long-term, and the ranges of funding required for each of the required programmes – all subject to securing required funding.

It’s a 12-week project that will further support the immediate emergency works, helping to form a strategic view of the current and future desired state of transport networks. The outcomes from the strategic approach will then feed into the collaborative delivery model set up for the recovery, which will see Waka Kotahi, KiwiRail, Downer, Fulton Hogan and Higgins build a team to plan exactly how the full scope of work will be delivered with local contractors in the years to follow.

And help, it seems, is on the way. In the Government’s budget last month, $20 million was committed for each of the next seven years, totalling $140 million, to fund a pipeline of low-cost, low-risk resilience works on local roads.

In addition, a further $279 million has been allocated for the next seven years for resilience works on state highways, with the spend certainly helping to mitigate risks associated with climate change, minimising damage and reducing future closure times.

“The damage caused by these weather events was significant and the rebuild and recovery will take time. We know we will continue to experience weather events of this nature and the continued resilience of our state highway network is essential to ensuring safe, reliable connections for our communities,” Mrs Hankin says.

“Building future resilience into the transport network, as well as taking action to adapt to the environment will be critical to delivering long-term permanent solutions. Essentially, the state highway network needs to be better able to withstand future weather events, in terms of both the initial impact and returning to expected levels of service quickly.”

Moving ahead, there are still some major announcements yet to be made, as Waka Kotahi continues to work with the resources they have to bring some level of business as usual back to the lives of everyday road users.

With no wayward pun intended, there is a long, long road ahead and the magnitude and impact of a 300–2000-year storm event is certainly being felt far and wide throughout the country.