Rethink of gorge needed

Calls for the road through the Manawatu¯ Gorge to open to one lane have come on the back of concerns about the time it will take to get a new alternative route up and running.

On October 11, the NZ Transport Agency announced a shortlist of four options for a replacement road to State Highway 3 through the gorge – which closed indefinitely in July.

The shortlisted routes come with expected completion times of between 5-7 years, an extension on the transport agency’s previous predictions of 3-4 years.

Horizons Regional Council chairman Bruce Gordon said given there were conflicting reports about whether or not the gorge could ever be reopened, using one lane should at least be considered.

Some, including a consortium of contractors, were determined it could be done, Gordon said.

The contractors wanted to reopen the gorge within two years by raising the road by 15 metres, using loose rock and dirt from the cliff face, and then cutting a ‘‘safety zone’’ to contain future slips. The idea was rejected by the transport agency.

Gordon said the consortium hadn’t been given the credibility it deserved.

He didn’t think the gorge was viable long term, but said he hadn’t had a satisfactory reason as to why it couldn’t be opened at least one way.

Agency regional transport systems manager Ross I’anson said there was still mass land movement at Kerry’s Wall, near the Ashhurst end.

‘‘It’s just too dangerous. We can’t afford to put people in there.’’

If the situation changed, there was still potential to open the gorge, but it wasn’t likely at this stage, I’anson said.

Two slips of about 3500 cubic metres prompted the gorge closure in April and since then, the transport agency has predicted up to 630,000cum could fall at Kerry’s Wall.

Previously, movement of the hillside was about 60 millimetres over 18 months, but this increased to 80mm in August alone.

This month, a large crack formed at Kerry’s Wall, further emphasising it was too risky to send workers in, he said.

In the meantime, the Manawatu¯ Chamber of Commerce has raised concerns the timeframes for the alternative routes could lengthen, causing an even greater loss to the local economy.

Chamber chief executive Amanda Linsley said there appeared to be inconsistencies between the latest information about the alternative routes and a 2012 report from the transport agency.

‘‘It could follow that the timescale may increase.’’

This could increase the loss to the region’s economy, estimated conservatively at $100,000 a day, Linsley said.

The four shortlisted options are an upgrade to the Saddle Rd, a new road north of the Saddle Rd, a new road south of it and a new road south of the Manawatu¯ Gorge.

The current alternatives to the gorge – the Saddle Rd and the Pahiatua Track – can take up to 30 minutes longer.

Information from the transport agency shows all shortlisted gorge-replacement options are expected to be at least two minutes faster than the gorge.

When measured from the intersection of SH3 and Stoney Creek Rd, to the intersection of SH2 and SH3 at Woodville, the gorge route took about 18-20 minutes.

Of the shortlisted options, the routes south of the Saddle Rd and south of the gorge would be the fastest – estimated at 13-16 minutes.

I’anson said the transport agency was confident its measurements were correct.

If the routes were different, it would only be by a few hundred metres, he said.