Last updated: 29 November 2019
What is being done about the slip?
Waka Kotahi NZ Transport Agency and KiwiRail geotechnical advisors have been investigating short and long-term solutions to return Omoto to a safe highway and rail link.
The team have drilled a number of bore holes and dug test pits in the ground. Information gathered has been used to create models of what the ground looks like, analyse why it is behaving the way it is, and to test how to stop movement to allow the road and rail link to be fully repaired and ensure resilience.
A drill rig has installed drain holes to drain water from the slip surface to stabilise the land in order to carry out repairs. The site is being regularly monitored for ground movement.
Longer-term, geotechnical advisors are working on a solution to reduce the potential for continued movement.
What damage has there been?
Wet weather and saturated ground resulted in ground movement, requiring traffic control and single lane traffic at the Omoto section of SH7.
More than five metres of ground movement was detected in one October weekend – and more than 15 metres was recorded from mid-August to the end of October.
As well as interruptions to road and rail, damage occurred to infrastructure below the ground, such as phone and fibre cables and underground pipes.
We are working with infrastructure providers to retain and protect their assets long-term.
Successful stabilisation strategies have meant SH7 has opened to traffic sooner than anticipated and rail services are restored.
SH7 Omoto East landslide photo gallery
How long will it take before full services are restored?
Long-term stabilisation works are expected to begin in January 2020.
Waka Kotahi NZ Transport Agency and KiwiRail are working with our geotechnical advisors to finalise long-term remediation of the site and resilience of the line and road.
Currently, SH7 through Omoto is open two-land, two-way, with traffic management in place.
The road surface in place now is temporary. Permanent reconstruction of the road will happen next year, once stabilisation works at the Omoto landslide are complete.
In the meantime, all road users are expected to follow temporary traffic management, including speed restriction.
The Omoto section of SH7 will be an active work site for a while yet. Short delays could be possible, so plan your journey accordingly.
Full rail services have been restored.
What will happen in the meantime?
There may be some short delays for people travelling SH7 through Omoto, due to lane this section of highway being an active work site and traffic management.
We thank people for their patience while we work as quickly as we can on long-term remedies for the site.
We will provide updates on progress accordingly.
Why was road and rail built on an historically active slip?
The road and rail line were built more than 150 years ago at the SH7 Omoto site, before anyone was aware there was an active slip.
Since then, the road and railway between Greymouth and Kaiata have been affected by landslide activity at a number of locations through this area.
This landslide represents a very small portion of the Omoto Complex.
Since the 1980s, the road here has been relatively stable and easily managed by highway crews with minimal disruption for road and rail users.
