Unstable rock face keeps Manawatu Gorge closed

The Manawatu Gorge will remain closed to traffic for at least two weeks following a geotechnical assessment carried out on-site yesterday.

The assessment by a specialist geotechnical engineer has revealed tension cracks in the rock face above the road at the site of Thursday afternoon's slip near Ashhurst.

New Zealand Transport Agency regional performance manager Mark Owen said that while the amount of debris that fell in the slip was not large, the unstable state of the rock face above the slip site meant the road could not be re-opened to motorists for safety reasons.

"The engineer's advice is that these cracks have rendered this rock face unstable, and the site is prone to further rock falls, which makes it unsafe for motorists until the unstable rock can be removed.

"We know that this is a critical route for the region, but the safety of motorists is our number one priority and we need to be sure that the site is stable before we reopen SH3.

"We understand that closures like this are frustrating and have a significant impact on people and on businesses. That's why we've put a lot of work into making both SH3 and the alternate routes on the local road network more resilient over recent years.

"Those alternate routes will remain open while we work to stabilise the rock face at the slip site and get SH3 open for traffic as soon as possible," said Mr Owen.

He said specialised equipment would be required to remove the unstable rock at the site of the slip - that was likely to involve the use of compressed air machines. That equipment would be found during the weekend and work would begin on Monday.

Regular (daily) updates would be provided to keep people informed on progress.

Motorists were advised to take the Saddle Rd between Ashhurst and Woodville.

Mr Owen also asked drivers to take extra care while using alternate routes with heavy rain forecast in the region at times during the weekend.

A massive slip closed the gorge in August 2011. The slip was cleared and the road reopened for three days, before being closed after another slip in October. It reopened 15 months later, after extensive engineering and strengthening work.