Highway not likely to open before end of next week

SLIPPING AWAY: The massive slip which closed the Manawatu Gorge road for nine months in 2011-2012, costing $21 million in repairs and other costs. PHOTO/FILE

The Manawatu Gorge seems unlikely to reopen in time for Queen's Birthday weekend in what is now its third-biggest closure in the last 13 years.

A spokesman for national highways authority the New Zealand Transport Agency said yesterday the gorge, closed since April 24, is not likely to open before the end of next week, and highways users are being told on the NZTA website not to expect a further statement on the closure/reopening of the road until June 2.

Hopes of reopening the State Highway 3 link between Woodville and Ashhurst this week vanished when it was discovered a retaining wall supporting the road near the Ashhurst end had shifted and would need replacing.

Regional highway manager Ross l'Anson was on site in the gorge yesterday and unable to be contacted, but the spokesman said "The timeline for reopening will of course depend on how quickly the repair work can be carried out, in a constrained environment and challenging conditions.

"Our crews will be doing everything to get the job done as soon as possible," he said. "It's unlikely to be before the end of next week, but if work progresses more quickly than expected we will open sooner."

Rain is forecast in the Palmerston North to Dannevirke area, as well as further north in Hawke's Bay, through the weekend and into the new week.

According to Hawke's Bay Today reports, the closure, which will by next Friday have lasted 39 days, is at least the 10th caused by slips in the gorge in the last 13 years.

The biggest was for 13 months after a major slip on August 18, 2011 and other rock falls, requiring the removal of what contractor MWH said was the largest road landslide in New Zealand history - 140m wide with a crest 130m above the road.

It was calculated the 40,000 cubic metres of material removed was enough to fill Napier's McLean Park or Wellington's Westpac Stadium to the tops of the grandstands.

"While the initial slip was considered large, the ongoing regression and final remedial design was far bigger than anyone initially comprehended," according to the MWH website.

The next biggest was in 2004, a year of several closures in which the longest was 70 days after a major February storm. It was reported at the time there'd been a similar closure in 1995.

Costs of repairing and maintaining the gorge and the alternative Saddle Rd and Pahiatua Track alternatives over the last 13 years weren't available, but the 2011-2012 event cost about $21 million, and the NZTA is currently investing $8.5m in upgrading Saddle Rd to the north of the gorge expected to be completed by the beginning of next year.

"Once we've done all that, we'll evaluate the options again, talk with regional partners and confirm whether the investment in Saddle Rd, as an alternate road, is sufficient," the spokesman said.

Costs of alternatives seem to rule out most other hopes, with a 2015 report estimating it would cost $120m to build a new road or roads north or south of the gorge, $450m for a gorge road including a series of bridges across the river, or $1.8 billion for a tunnel.

Highways claimed a big share of the Budget 2017 infrastructure allocation, with $9.2b earmarked for 540 new "lane kilometres" of state highway over the next four years, but neither the gorge nor anywhere in Hawke's Bay figure in the 10 key projects.