Essential work only on Manawatū Gorge replacement highway but new road on track

Friday, 20 August 2021

A temporary bridge over the Manawatū River at the Ashhurst end will allow for construction on the 300-metre Parahaki Bridge.

The coronavirus lockdown has halted all but essential work on the new highway linking Manawatū and Hawke's Bay, but construction will resume with a drop to alert level 3.

Work on the $620 million Te Ahu a Turanga Manawatū Tararua Highway, a replacement for the closed State Highway 3 through the Manawatū Gorge, is ahead of schedule as the project emerges from its winter season.

It's 10 years since a slip on the old SH3 heralded a 14-month closure and calls for an alternative east-west route.

A 2017 slip shut SH3 permanently and construction of the new Ashhurst-Woodville highway began in January, with an expected completion date of the end of 2024.

* Highway work heads into winter construction season

* Bridge works begin on Manawatū Gorge replacement highway

The work site at the Ashhurst end of the project was quiet on Friday.

Waka Kotahi NZ Transport Agency project spokesman Lonnie Dalzell said construction had temporarily stopped because of the lockdown, but was expected to resume when the region dropped to level 3.

“The only work we’ve got on under level 4 is essential, either maintenance, environment or health and safety,” he said. “[For] level 3, we’ll get our plans up to date and get ready to go.”

What exactly the project alliance would be able to do would depend on what the Government and project safety plans allowed.

A temporary bridge across the Manawatū River at the Ashhurst end of the gorge, where the road begins before rising up the Ruahine Range, is complete.

The new highway will head out of Ashhurst, over the river and climb up the lower slopes of the Ruahine Range.

It will allow construction work on the 300-metre Parahaki Bridge over the river from its central pier outwards. Pier construction is about to begin.

Dalzell said workers would drill about 30 metres into the ground for the pier piling. People would be able to see progress above ground towards the end of the year.

The southern slopes of the range were changing shape. This was particularly visible from the Woodville end.

“When you're driving on the current highway, Saddle Rd, you can see the earthworks all the way up to the ridge line.”

Lonnie Dalzell, pictured earlier in 2021, says highway construction is on track as the winter season draws to a close.

Already, more than 500,000 cubic metres of material had been moved by workers smoothing the way for the 11.5 kilometre road. It will take motorists about 13 minutes to drive, far quicker than the windy Saddle Rd.

Dalzell said work was ahead of schedule after a good winter.

Just beyond the temporary bridge a railway crossing would be built for construction vehicles. It would be managed by a qualified rail protection officer.

When the Parahaki Bridge's pier on that side of the river was done, construction would move above the railway.

Work on an eco-viaduct on that side had encountered “engineering issues”. It will take the road above sensitive ecological areas.

About 200 workers, including sub-contractors, were on the site. That was expected to increase to 250-300 when earthworks ramped up from October.

As part of the project, about 1.8 million plants will go in the ground. By the end of winter about 200,000 were expected to be planted. Already, more than 130,000 had been and there was about a month of planting weather left.

The genesis of the new highway was on August 18, 2011, when a slip fell on SH3 at the Ashhurst end. A series of falls, including a large one in October that year, resulted in a 14-month closure and intense debate about the viability of the route, after previous closures down the decades.

In that closure and the latest one, Saddle Rd became the main east-west route.

Waka Kotahi director or regional relationships Linda Stewart said that increased traffic on the road from 200 vehicles a day to more than 6000.

Since 2017 Waka Kotahi, which took over maintenance and management of the road from the Tararua District Council, had spent about $2 million a year on improvements, such as installing guardrails and straightening corners. There had been a reduction in accidents, such as trucks rolling.

In 2011-12 about $4m was spent.