Solving the Rocks Rd problem
Nelson’s traffic ground to a standstill last week as commuters faced a closed Rocks Rd.
It was the third time in as many weeks the road was closed, with the series of rain events that caused widespread flooding throughout the region also bringing slips down on one of the city’s key routes.
The latest closure saw the waterfront road shut on July 11 as heavy rain lashed the region, loosening rocks, vegetation and other material on the cliff face above the state highway.
The road was reopened at 6pm on Friday after more than 650 tonnes of loose material was removed during the week.
NZ Transport Agency Waka Kotahi system manager Nelson/Tasman Rob Service said a rock from the cliff face had dented a tradesman’s vehicle 45 minutes before the closure, and material had fallen intermittently in the days that followed.
Chunks of an old concrete crib wall had also fallen, with some pieces bouncing across State Highway 6 into the water.
“If a pedestrian, cyclist or motorist had been there, that would have been catastrophic,” Service said.
The ongoing slips raise the question: what needs to happen to make Rocks Rd safe and secure?
Service said the cliff face and the surrounding areas were “complex environmental and geological systems“.
Some aspects, such as privately owned land, were outside the direct control of NZTA, he said.
“Where possible, we work with private landowners, as well as Nelson City Council to mitigate these risks.”
Rocks Rd was regularly checked and had annual geotechnical inspections, he said.
“NZTA Waka Kotahi has carried out work over recent years to address the areas of highest risk to help make the rock face more stable and safer, focussing on reducing the potential for material falling onto the road.”
That work included drainage pipes, netting and anchored mesh, spraying the cliff with shotcrete to seal parts most likely to fail, anchoring the cliff face, and controlled removal of debris, Service said.
For medium to high-risk sections, NZTA planned to make closer inspections by rope, remove debris, and install more rock anchors in combination with an anchored mesh system.
“For lower risk sections contractors will continue to monitor these areas and clear drains and debris as required.”
Service said engagement with clifftop property owners had begun and the agency was working through a number of options with engineers to come up with a permanent solution to reduce the number of closures.
Nelson mayor Nick Smith said the sheer volume of rain this year had been “truly exceptional”.
Both NZTA and the council recognised the disruption caused when the road was closed and were exploring further steps to improve its resilience, he said.
That could be extending areas covered by rockcrete, or other geotechnical technologies for capturing slip material at the base and adjacent to the highway.
“We also need to be open that Rocks Rd has faced these slips and these problems both from the cliffs, but also during major northerly storm surges, where it has to be closed as well.
“It is not the ideal state highway route, but, for the medium term, it’s the best we’ve got.”
The Hope Bypass remained the region’s most pressing transport project, he said.
In 2024 plans to improve safety along the Rocks Rd section of State Highway 6 around Nelson’s waterfront were dropped from the high-level Government Policy Statement (GPS) on Land Transport, after the previous Labour Government had included it alongside the Hope Bypass as a priority project for the region.
Also in 2024, NZTA released its 10-year State Highway Investment Programme (SHIP), which identifies projects for the network in line with Government strategy. There was no mention of Rocks Rd.
Nelson MP, Labour’s Rachel Boyack, said Labour’s plan had been to improve the seawall, which was one part of the resilience solution for Rocks Rd, and she acknowledged it would not have solved the issue of slips from the cliff above.
“They’re connected, but they are different resilience issues and more work does need to go into, you know, preventing those slips.“
With closures causing traffic disruption and frustration “NZTA and the council need to work closely to get some work underway on that as soon as possible”, she said.
Transport Minister Chris Bishop said “Nelson-Tasman district’s transport needs are very much on my radar”.
“[On Wednesday] I had a productive meeting with local government leaders, including Nelson’s mayor, about transport issues and priorities across the South Island.”
NZTA was working on recovery plans for the state highway network affected by flood and slip damage, he said.
“The previous government’s $200 million SH6 Rocks Rd project would not have helped in the recent slips. That project involved building a new sea wall and cycleway on the seaward side of the road and did not involve any significant improvements to the hill side of the road, or any measures to improve resilience from rockfalls.”
For hospitality and retail businesses just past the Rocks Rd cordon, it has been a difficult few weeks.
Olivia Alden, general manager of The Boathouse, said the road closures had a “massive impact” on business, costing them three Friday nights of trade — their most important revenue opportunity each week.
“Winter’s already tough because people hibernate, but the road closure and rain hit just as people were starting to come back out,” she said. “We’ve had to cut staff shifts the last few Fridays, which I hate doing, but it’s the reality of business right now.”
She said the people at the closure points were helpful, but the signage still deterred customers. “We’re pushing on social media to say we’re open. At least this week they’ve moved the cones on Haven Rd so you can drive straight through.”
Alden said it was surprising the road had stayed closed all week despite the mild weather. “I know they’re doing what they can, but it’s such an important route.”
Georgia Hamilton, general manager at seafood retailer Guytons, said business had been very quiet following the road closure, though things had picked up slightly after the council began posting on social media to let people know access was still possible.
“They’ve done a couple of posts that mention us and other businesses – but there are still definitely fewer people driving around,” she said.
She said many people were confused by the “residents only” signage. “Unless they’re on social media, they just see the sign and get nervous about driving down. A lot of the businesses have had to put signs out to say, ‘We’re open’ down by the road cones.”
Rhianna Vavit, a manager at Styx, said the biggest impact had been people not realising the restaurant was still open.
“We’ve had to rely on the community through Facebook to spread the word,” she said. “With the detours, it’s easier for people to just dine in the city centre.”
The closure forced them to cut staff shifts and cancel live music, but she said the local support had been strong in the last few days. “We’ve had a really good community come in and back us.”
By Warren Gable, Nelson Mail
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