TREC Tairāwhiti recovery update

Issue 22

30 May 2025

Tēnā koe

In this edition, you can read about how we’re working with nature to tackle challenges on State Highway 35 (SH35), get the latest update on our work in the Mangahauini Gorge, and check in on progress at Otoko Hill on State Highway 2 (SH2).

Planning to hit the road over the King’s Birthday long weekend? Most state highway roadworks will stop from 12pm today (Friday 30 May) and restart Tuesday morning (3 June) to keep traffic flowing when it's busy.

A few sites – for example, for emergency repairs – will continue and some sites will have traffic management in place for safety.

Thanks for your patience as we continue our recovery mahi.

SH35: Mangahauini Gorge update

Soil nails are being used to reinforce unstable slopes across Tairāwhiti, and Mangahauini Gorge - with its river scour, slips, and tough terrain - is no exception.

This week, crews began installing 160 soil nails at the Mangahauini Gabion Wall site, a process set to take around 3 months. SH35 through the gorge remains down to 1 lane, with stop/ go traffic management in place.

Meanwhile, preparations are underway for the next phase of recovery work in the gorge. This is expected to include drainage upgrades, river-grade control, a highway rebuild, and riverbank stabilisation.

We’re working closely with Iwi, landowners and others to make this happen - stay tuned for updates on when work will start.

The blue crosses in this image show where individual soil nails will be drilled. You can also see rock armouring the team has added to protect against erosion.

Working with nature to strengthen SH35

A ‘living wall’ of willow trees is taking root by SH35 at Kemps Hill, reinforcing the landscape with nature’s own engineering.

With deep roots and incredible flexibility, willows act like anchors, locking soil in place and stabilising the slope. As they grow, their intertwining roots form a natural shield that will strengthen the hillside and make it more resilient against extreme weather.

They’re perfect for sites like Kemps Hill, where we’re repairing 3 underslips that have reduced SH35 to a single lane. 

In the photo below you can see the willow trees laid horizontally, which is how they have been planted. This might seem strange, but it helps the roots grow into the hillside. Once established, the trees grow upright.  The willows used here are sterile, so they won’t spread or become invasive.

Blackbee Contractors are also reinforcing the road with engineered fill, creating a solid foundation beside the willow wall.

A willow wall will also be used on our SH2 Matawai Road site. Work to stabilise a slip gets underway this week.

Willow wall construction underway at Kemps Hill.

Did you know?

Willow walls aren’t new - they were widely used to stabilise roadside slips and riverbanks in New Zealand from the 1940s to 1960s - but they’re making a comeback. Low-cost and environmentally friendly, they prove that nature still offers some of the best solutions to our toughest challenges.

SH2: Work at Allen’s Existing Wall

Throwback to late February when the weather was warmer! This video captures progress at our Allen’s Existing Wall site on SH2, where crews from Currie Construction have been working to repair a retaining wall and improve drainage below the road.

This project is on track to be complete in June. Stay tuned for more updates as we get closer to the finish line.

Back to 2 lanes at Opape

Before finishing a project, we do a ‘final walkover’ – a last check to make sure everything is safe, stable and ready for the community.   

Last week, Ngai Tamahaua hapū, kaitiaki and Hicks Bay Drainage joined the TREC team at our SH35 Opapae site for this crucial step.

After months of hard work - building a gabion wall, upgrading drainage, strengthening the road and resealing - the site passed with flying colours.

The team is working to complete line marking and install edge markers.

Top photo: The team at the walkover. Bottom photo: The new gabion wall and drainage system, which will help stabilise the ground and prevent erosion in the future.

SH35 Makatote

We expect to be back at SH35 Makatote, near Waipiro, next month.

The highway here will be down to 1 lane until late July while crews reinforce the area with rock armouring (to protect against erosion) and complete pavement upgrades. Traffic lights are in place.

Please allow for delays of up to 5 minutes when travelling through.

SH35: Hikuwai Bridge update

The TREC Liaison Group (TLG) meeting was held on-site at Hikuwai this week, where we also celebrated the opening of the new site offices. 

It was a great chance to connect and look at the work being done. 

The site offices will be busy with over 50 people on-site during the project’s peak.

Enabling works are almost done:

• Demolitions are complete, and Currie Construction finished up last week.
• Parata Construction is working on the new bypass at the southern end of the Bailey bridge, which is expected to open to traffic in June.
• Some additional earthworks are planned, with the final enabling works wrapping up around the middle of July. 

The Hikuwai TREC team is working hard to prepare for the arrival of the main bridge subcontractors in the coming months. We’ll share more on that soon.

Find out more about this project: SH35 Hikuwai Bridge No.1 replacement.

TREC, NZTA and members of the Hikuwai TREC Liaison Group (TLG) on site.

Removal of remaining Hikuwai pier

As work progresses towards a permanent replacement for Hikuwai Bridge No. 1 north of Tolaga Bay, the last of the old bridge, and the sole standing pier damaged by Cyclone Gabrielle, has now been removed. 

An experienced local demolition team from Currie Construction used a technique that involved drilling holes into the lower columns to remove concrete and weaken the base, before a controlled lowering of the pier onto the northern banks of the Hikuwai River.

The pier being removed.

SH2: Otoko Hill update

It’s all go on Otoko Hill. The big news: Site G is almost done.

Crews have reinforced the hillside with soil nails and shotcrete and resealed the road. Just a few final touches remain before the team packs up, with plans to return in summer to complete the final seal on the corner.

• At Site J, drainage and retaining wall work continues, with the team currently installing waler beams to reinforce the area and installing counterfort drains.
• Crews working on counterfort drains and culvert repairs at Site B have reached the half-way point.
• A reminder to allow an extra 5 to 10 minutes when travelling on SH2 in this area. Stop/go traffic lights and speed restrictions are in place.

State highway snapshot

Below is a snapshot of construction works either underway or coming soon. You can also view completed, current and future work sites on our interactive map.

Here are some of the construction terms we use:

• Buttress – supporting structure
• Counterfort drain – drain that improves slope stability by controlling groundwater
• Dolosse - interlocking concrete blocks
• Gabion wall - baskets filled with rocks
• MSE (Mechanically Stabilised Earth) – a retaining wall construction technique used to stabilise slopes
• Rip rap - large rocks
• Rock revetment – protection
• Scour - erosion
• Shotcrete – sprayed liquid concrete
• Soil anchors/soil nails – a device used to hold, restrain and support structures
• Willow wall – using willows as ‘living walls’ to stabilise slips

SH2 underway (see Otoko map above)

• Otoko Hill (site B) – tree removal and major drainage to stabilise slopes
• Otoko Hill (site J) – retaining wall repairs and drainage installation
• Rakauroa – repair underslip using soil anchors and shotcrete
• Matawai Road – willow wall to stabilise slip.

SH35 underway

• Matawai Road – willow wall to stabilise slip
• Hikuwai Bridge No.1 replacement – enabling (early) works
• Mangahauini Gorge - investigations to support future recovery work
• Mangahauini Gabion Wall – Stage 2 – soil nails, buttress and rip rap at the bottom of the existing gabion wall
• Kopuaroa Slip 1 – reinstate SH35 to 2 lanes by installing a soil anchor and shotcrete wall
• Kopuaroa Slip 2 – build a 250m long buttress to support SH35 and provide additional drainage
• Opape underslip – buttress repair with gabion wall
• Tōrere – underslip and overslip repairs
• Paronga – buttress wall with MSE. Two faults to be repaired to reinstate state highway to 2 lanes
• Kemps Hill subsidence – buttress repair using a willow wall. Three faults to be repaired to reinstate state highway to 2 lanes.

SH35 coming soon

• Rotokautuku (Waiapu) Bridge revetment – repair the scour at the south end of the bridge and construct a major revetment with dolosse for future-proofing
• Rotokautuku (Waiapu) Bridge repairs – strengthening works
• Makatote dropout #2 – buttress support and rip rap to prevent future river erosion
• Makatote dropout #3 – reinstating state highway to 2 lanes, buttress support and rip rap to prevent future river erosion.

Whakapā mai – Get in touch

• Email us
• Website
• LinkedIn
• Facebook
• Call us: 0800 80 TREC (0800 80 8732)

If you spot an issue at a work site after hours, call 0800 4 HIGHWAYS (0800 444449).

Sign-up to receive these regular newsletters:

• TREC Pānui (general newsletter)
• TREC Hawke's Bay regional update
• This TREC Tairāwhiti regional update

Local road network

Gisborne District Council is responsible for local roading recovery projects. More information.

Up-to-date information on local road closures.