Long-term solution to Manawatu Gorge troubles at least six years away, says logistics specialist

Monday, 14 August 2017

One of the slips on State Highway 3 through the Manawatu Gorge.

Despite promises of pace, a permanent alternative to the Manawatu Gorge road is at least six years away, according to a logistics specialist.

Giancarlo Hannan, a senior logistics analyst for Palmerston North company Corporate Logistics Ltd, has released a six-page report called The Achilles Heel of State Highway 3.

The Manawatu Gorge slip, blocking State Highway 3 at the Woodville end.

He said procrastination over settling on an alternative link had caused $100 million to be spent on the 145-year-old route since 2004, while its closure cost the regional economy about $100,000 per day, according to conservative estimates.

Hannan's report says it has taken the Government 13 years to seriously explore a solution. It also details the causes of the road's closure, and examines four possible alternative routes.

The road through the Manawatu Gorge has been closed indefinitely since July.

* Manawatu Gorge closure a chance for more 'resilient' route, says minister

* Anger, concern over Manawatu Gorge closure

* Manawatu Gorge closure causes strain on two towns

* SH3 Manawatu Gorge Alternative Route report 2012**

The routes are the four options detailed in the November 2012 report prepared for the NZ Transport Agency. Hannan said that report came to the conclusion 'a long-term solution will be at least seven to 10 years away'.

No progress had been made on the alternatives since that report.

SH3 through the gorge has been closed by slips since April, and last month the road was closed indefinitely because of fears about the stability of the hillside.

Regional transport manager Ross I'Anson said the agency was in the process of undertaking a detailed business case on possible options for an alternative east-west route.

'We will know more about the potential options by the end of August and what their timelines would be. A final option will be decided upon by December 2017,' l'Anson said. There would then be public consultation.

In July, a transport agency official told a Woodville community meeting that a permanent fix was expected within three years.

Hannan said he didn't see how that was possible. While actual construction of an alternative route could take three years, so could the planning, purchase, consents and compliance process.

'With due diligence and perhaps with the relocation of some wind turbines – depending on the route chosen – it will be three years before there's even a peg in the ground.'

A spokesman for Transport Minister Simon Bridges said he had never put any timeline on delivery of the project.'The Government is committing to provide a permanent, greatly improved, much more resilient route,' Bridges said in a statement last week.

'The NZ Transport Agency is progressing this work much more quickly than normal timelines because of the importance of finding a long-term solution for this important connection.'

Of the four gorge alternatives, Hannan preferred the Greenfields route, an almost 6-kilometre-long straight cut through the Tararua Range from the Fitzherbert East Rd-Napier Rd junction to the Ballance Bridge.

It would require the excavation of a whopping 52 million cubic metres of soil, a 200m-deep cut to make the gradient manageable for trucks and the removal of eight wind turbines.

His second preference is for the bridging and viaduct option along the present route. While Hannan said it would be a terrific scenic drawcard, there was also the risk of deep-seated slope failure.

The nearly 5.5km-long tunnel option at $1.8 billion was the most expensive and cut through two major active fault lines.

'I wouldn't want to be in there in an earthquake.'

A fourth option, known as Worley Rd, crosses the river at the Ashhurst end of the gorge, and sweeps north, crossing the Saddle Rd to come out of the Ruahine Range above the existing route to link with Woodlands Rd.

While it had a gentle gradient and was potentially the least expensive, it added 5km to the distance, and would require extensive land purchases, along with the possible removal of three turbines. Logistically, this was Hannan's least-favoured option.