The Crown Range Road is likely to be closed for two weeks to stabilise a large bluff which has begun to collapse across the road.

Persistent, heavy rains throughout September and October created a number of slips on the Crown Range, particularly to the section of switchbacks nearest to the Arrowtown turnoff, which had reduced traffic to single lanes in places, Queenstown Lakes District Council (QLDC) staff said. 

Although more than 300m3 of debris has encroached on the road, most of the 16 slips are considered “minor”, QLDC operations manager Simon Mason said. The minor slips will be cleared first while the road remains open to traffic.

But a large bluff on the Cardrona side of the alpine pass has partially collapsed, breaking through its wooden restraining barrier, known as a catch fence, onto the roadside.

“The scale, complexity and safety requirements of work on the larger slip is likely to require closure of the Crown Range Road during the day for approximately two weeks (it will reopen each evening),” Simon said. 

Most of the work will be carried out by QLDC’s road maintenance contractor, Downer.

It’s not yet known when the road closure will take place but the dates and site-specific traffic management plans “will be widely promoted in advance so drivers can make alternative plans”, Simon said.

During the planned closure, traffic will be diverted to use State Highway 6 via Cromwell and the Kawerau Gorge.

Simon said the closure will also provide an opportunity for a thorough inspection and maintenance along the whole road. 

“This is likely to cover sweeping/cleaning, pavement work, fixing minor potholes and edge breaks, and checking signage,” he said.

Broken posts and boards will need to be replaced and tonnes of debris removed from several slips on the Crown Range road.

This route is a vulnerable alpine pass that’s susceptible to damage caused by extreme weather and temperatures, he said.

“The effects of climate change mean it’s likely we’ll see more frequent extreme weather events and hence a greater number of slips along the Crown Range and similar roads.”

Simon said some “resilience improvement” funding had already been approved by New Zealand Transport Authority (NZTA) under the 2024-2027 National Land Transport Plan.

An application to NZTA for additional emergency works funding was underway but there was no guarantee funds would be available and council would have to reprioritise existing budgets to cover the shortfall, he said.

Cardrona Valley Road: 80k temporary speed limit

Work will also resume on the safety improvements to Cardrona Valley Road this week.

Earlier this year, a section of the road was placed under a temporary 80k speed limit while drainage, geometric improvements (reshaping road curves and corners), and safety barriers (guardrails) were installed.

While the improvements were only partially completed before the winter months stopped all work, the temporary speed limits remained in place as the unfinished works were considered a risk to traffic.

Fulton Hogan will stage the remaining work in two sections; the first will be completed before Christmas and the second after.

“We had hoped to start earlier but recent poor weather (that also caused the slips) has delayed things,” Simon said.

The estimated total cost is $4.5M. At the time the work was committed, NZTA was funding 51 percent of the project. Under the new funding model, however, NZTA’s funding assistance has reduced and council will now fund the shortfall, Simon said. 

PHOTOS: Supplied