Ngaio Gorge Stabilisation

Major strengthening is happening in Ngaio Gorge to make this key transport route stronger and more resilient.

In 2017, a new 42-metre-long retaining wall was built below the road about half way up the gorge.

In 2018, work was done on the upper section of Ngaio Gorge – removing loose material, stabilising the site, and installing monitoring equipment.

Future Ngaio Gorge slope stabilisation

The Council plans stabilisation and reinforcement work in Ngaio Gorge to improve the safety and accessibility of the area following the landslides of July 2017. 
This work is part of the Council’s ongoing programme to strengthen important transport routes, and improve the safety and accessibility of Wellington’s wider transport infrastructure. 

Construction work is scheduled to get underway at the start of September 2019 and will run through until October 2020. There will be impacts on traffic while the work is underway, but these will be communicated well in advance with necessary diversions put in place. 

What's being done

After careful consideration of multiple options the Council has decided on the following actions: 

  • Erecting three retaining walls along the edge of the new road alignment
  • realigning the road on both sites to provide space for the slope hazard mitigation work
  • implementing targeted slope hazard mitigation with scaling, anchors and mesh reinforcement as well as catch fences
  • removal of temporary shipping container wall.

Next steps

  • January 2019: Geotechnical ground investigation will start 
  • Mid-2019: The Council aims to select a main construction contractor