Gorge alternative shortlist revealed
The potential alternative routes to the Manawatu¯ Gorge have been whittled down to four options, but they could take up to 7 years to complete.
On Wednesday, the NZ Transport Agency revealed the four frontrunners from the list of 13 alternative routes released last month.
The four shortlisted routes are; an upgrade to the existing Saddle Rd, a new road north of the Saddle road, a new road south of the Saddle Rd and a new road south of the Manawatu¯ Gorge.
The chosen routes are expected to cost between $300 million and $550m and will take between 5-7 years to complete.
State Highway 3 through the gorge has been closed since April when several slips fell and blocked the road. In July, the highway, the main link between Manawatu¯ and Hawke’s Bay, was closed indefinitely after the hillside was deemed too unstable.
At a public meeting last month, transport agency regional transport systems manager Ross I’Anson said the aim was to have an alternative route complete within 3-4 years.
The cheapest shortlisted option is the 13.8 kilometre Saddle Rd upgrade, which is expected to cost between $300-$400m and take between 5-6 years to complete.
The longest of the four shortlisted options, a 19.2km route south of the gorge, is the most expensive and will take 6-7 years to complete at a cost of $450-550m.
Maps released by the agency showing the alternative routes depict route ‘‘corridors’’ about 300 metres wide, I’Anson said. The exact route would then fall somewhere inside that space.
I’Anson said the agency now better understood the complexities and the size of the project.
The new timeframes were conservative, so he was confident the chosen route would be completed within its expected timeframe.
A top preferred option would be chosen by December.
All options through the gorge had been ruled out, he said.
A full tunnel through the gorge could have cost up to $2.2 billion and a viaduct could have cost up to $1.4b.
‘‘No matter what we do in the gorge it will not be resilient.’’
The agency was monitoring the gorge and if the hillside stopped moving, it would consider opening it again, I’Anson said.
The agency doesn’t have a record of how many slips have come down since the gorge closed, but spokesman Andrew Knackstedt said about 27,000 cubic metres of material had fallen since April 24.
About 10,000cum has been taken out of the gorge and about 15,000cum of material is still on the road.
If the Saddle Rd upgrade is the final route chosen, it may be closed off at times, meaning motorists would have to take the Pahiatua Track, south of the gorge.
However, most of the work would take place off the existing road, so it was hoped traffic would not be affected too much if it was chosen, I’Anson said.
A public meeting to discuss the options is being held in Palmerston North this afternoon, while further meetings in Woodville and Ashhurst will be held on Thursday and Friday respectively.
State Highway 3 through Manawatu Gorge has been closed since April 2017.