The Manawatu Gorge section of State Highway 3 is one of the most difficult roads in New Zealand to work on. This narrow road is carved into the side of the gorge 20 metres above a river. The road is a vital transport link for communities on the east and west of the central North Island.
In October 2011 a destructive landslide struck. Measuring 140 metres wide and with a crest 130 metres above the road, this is the largest road landslide in New Zealand’s history.
MWH Global was the New Zealand Transport Agency’s (NZTA) network consultant and geotechnical engineer for the project. Together with a team of specialist geologists, geotechnical engineers, client manager and contractor. MWH worked collaboratively, and with urgency, to reopen the highway.
MWH was responsible for:
The work carried out to stabilise and remediate the Manawatu Gorge slip has been a huge undertaking by all parties involved. While the initial slip was considered large, the on-going regression and final remedial design was far bigger than anyone initially comprehended. A collaborative team approach resulted in an expedient response and the safe removal of the slip material from the site by the end of May 2012. The road was opened to two-way traffic on 19 September 2012.
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“The crew have stuck at the task for a long time, and they can now reflect on a job well done. They’ve rebuilt an entirely new piece of highway in a superbly orchestrated blur of activity, and words can’t express the value of their hard work for the Manawatu region and beyond. Every cliché about true grit and Kiwi ‘number eight wire’ ingenuity comes to mind, but at the end of the day, they had a job to do – a huge job - and they did it.”
David McGonigal, NZ Transport Agency Palmerston North State Highways Manager
