Gorge costs mount

More slips have come down in the unstable Manawatu Gorge hillside as cleanup costs surge towards the $1 million mark.

Efforts to reopen State Highway 3 through the gorge took another hit last weekend when two small slips damaged rock-fall netting and support structures 4.5 kilometres from the Ashhurst end.

The main route between Manawatu and Hawke’s Bay has been closed since late April, when two slips came down.

Since then, more slips and damage to the roads have forced motorists on to the windy and steep alternatives – Saddle Rd and the Pahiatua Track.

This comes as figures obtained by the Standard reveal the estimated costs for the latest cleanup are $937,000.

The NZ Transport Agency says the money comes from emergency works funding. It is dwarfed by the $20m spent on the huge slip that closed the road in 2011/12.

Transport agency highway manager Ross I’anson said the latest slips would be considered as part of a ‘‘geotechnical assessment’’ looking at the stability of the notoriously temperamental Tararua Range side of the gorge.

Meanwhile, agency officials were still working on a ‘‘detailed business case’’ to look at ‘‘all of the options available to provide a longterm, resilient and safe connection through the Ruahine/tararua Ranges’’.

Some ideas were raised in a hefty 2012 report from the agency, including erecting bridges along some or all of the route.

The alternatives in the report cost between $120m, for a new road near Te Apiti wind farm, and $1.8 billion, for a tunnel. Upgrading Saddle Rd to ‘‘state-highway standards’’ is also a possibility.

‘‘Once a preferred option is developed, detailed investigations and cost estimates will be undertaken in order to inform a request to fund the project from the National Land Transport Programme,’’ I’anson said.