A new slip has formed on the southern end of the gorge after last week’s torrential rain.

SH1 Mangamuka Gorge Slip Repairs - May update

Kia ora koutou,

Enabling work at SH1 Mangamuka Gorge is progressing well, despite some setbacks and a few days of site closures over the past week due to extreme weather.

We are continuously monitoring ground conditions for additional slip movements, including during weather events. There has been some movement due to the recent torrential rain, including another minor slip under the road which will need to be repaired (pictured above).

Our crews are putting extra measures in place to keep everyone safe, and at times we may need to stop work if conditions become unsafe.

Despite being unable to work on site during the severe weather, our CLL crews were still able to help the community by clearing debris off Fairburn Road near Kaitaia so folks could travel through safely. A massive mihi to CLL for helping.

It’s a key priority for us to reopen SH1 Mangamuka Gorge as quickly as possible, and improve resilience across the Far North roading network into the future.

As part of this work, we are collaborating with a Far North working group which includes hapū, local stakeholders, technical experts and elected representatives to highlight the key priorities for the district. This feedback will be included in a business case due to be presented to the Waka Kotahi Board and we’ll share more about this long-term planning in due course.

We appreciate your understanding, patience, and support as we work through this.

Improved drainage by slip number 12.

Progress update

Our crews are continuing with enabling works which will ensure the gorge is safe and stable enough to accommodate the large machinery needed to carry out permanent slip repairs.

This has included installing hundreds of piles across the critical slip sites and we have now begun installing capping beams (these tie all the piles together) on multiple sites.

The permanent walls will be built adjacent to these and will then be anchored into the sturdy material in the mountainside to hold the road which will be built on top.

With approximately 700 piles to install across all sites this is a large piece of work. So far, we’ve completed all the interim piles at two of the main slips and are progressing ahead of schedule with piles across the other main sites.

Over the coming month, we’ll continue installing piles for enabling work and will progress with installing capping beams on two other slips. Check out the images at the bottom of this newsletter to see what our team have been up to.

Construction is being carried out like an assembly line, where our crews begin installing piles from the outermost slips and work their way toward the summit. Capping beam installation follows behind that.

We will begin the permanent slip repairs within the next month in the same fashion, beginning with the outermost slips on the north and south side and working inward toward the summit.

Need more information for your local community group?

Our latest flyer ensures you and your community are kept up to date.

If you would like some printed copies to hand out to your whānau or community group, send us an email at northlandproject@nzta.govt.nz with your name, mailing address and the number of copies you need. We’ll then pop them in the post directly to you.

To view the electronic version of the flyer, click here.

Progress on slip 3 – all of the temporary piles have been installed and approximately 50% of the permanent piles.

Progress on Slip 5 – 25% of the piles have been installed at this location.

Capping beam installation on Slips 1 and 2.

More information

For more information on the SH1 Mangamuka Gorge slip repairs, contact us at northlandproject@nzta.govt.nz

Visit our website www.nzta.govt.nz/mangamuka