TREC Tairāwhiti recovery update

Issue 29

5 September 2025

Tēnā koe

In this edition we provide an update on the next phase of work on State Highway 35 (SH35) in the Mangahauini Gorge, an exciting arrival for the Hikuwai Bridge project, and there’s a heads-up on upcoming flood resilience work at Rototahe.

We’d also love your feedback. Please take a minute to fill out our quick survey below and let us know what you think about this newsletter and what you’d like to see more of.

Thanks for your ongoing patience as we continue our recovery mahi.

Major works starting in Mangahauini

We’re kicking off the final and biggest stage of work in the Mangahauini Gorge, and it includes something special that’s a first for New Zealand!

Local crews have done an awesome job keeping 1 lane of SH35 through the gorge open since Cyclone Gabrielle, and now we’re moving into the long-term fix.

That means more action onsite and short delays if you’re driving through until we finish in mid-2026.

One of the key features is a new ‘roughened channel’ being built in the Mangahauini River. It’s believed to be the first of its kind in a river in our country.

Half a kilometre of the riverbed will be reshaped into the new channel through specially shaped concrete interlocking blocks (‘hanbars’), rocks and other material placed in the riverbed. This will slow the river where it’s steepest and most aggressive and help protect the highway.

Watch our short video below or find out more on our new project webpage.

Flood resilience work starting soon at Rototahe

Crews are gearing up to start work at Rototahe on SH35.

A 200m section of road will be lifted by almost 1 metre to help reduce flooding and keep the road open. 

Drainage will also be significantly improved to help remove water from the road and keep this critical route operating for motorists and emergency services. 

The project is expected to take around 6 months to complete. Work will take place Monday to Friday between 7am and 5pm under stop/go with traffic lights.  

For more information you can visit the Rototahe project webpage.

This flood-prone section of highway at Rototahe will be upgraded.

Team stands tall with arrival of first Hikuwai Bridge pile casings

It was an exciting day for the Hikuwai Bridge team with the arrival of the first pile casings that will help form the foundation of the new bridge.

These casings will be welded together and act as protective sleeves, helping to guide and support the piles as they’re driven up to 50m into the ground.

The huge steel tubes are around 12m long and 1.8m wide, giving everyone a real sense of the scale of work to come.

All 16 casings are expected to be delivered to Universal Engineering in Gisborne by next week.  They will be carefully checked by our teams to ensure they meet the highest quality standards.

A traffic switch at Hikuwai was also undertaken last week to move traffic from the existing SH35 route onto the new temporary road. This route will ensure a smooth journey for motorists throughout construction.

Thanks for driving with extra care and staying alert when travelling through.

Members of TREC's Quality and CPS teams with Universal Engineering Sales Director Phil Matthews stand tall within the first pile casings.

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We’re keen to hear your thoughts about the information you’re receiving on our Tairāwhiti reovery efforts.

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Massive culvert installation at Hakanui Straight

A 1.8m wide culvert (pipe) that’s big enough to stand up in will be installed at the State Highway 2 (SH2) Hakanui Straight flood resilience site this month.

Bigger than most culverts used across New Zealand’s state highway network, it will channel the Hakanui Stream beneath the road.

Its size reflects the scale of the challenge the project team is tackling as they work to improve the resilience of this flood-prone stretch of road.

Work on this project is ramping up. If you’re travelling through, please plan ahead for possible delays of up to 10 minutes.

Read more about work at Hakanui Straight.

TREC Site Engineer Javier Tapia with the new culvert pipe.

Anchored in place

Check out this great photo of our Allen’s Existing Wall project on SH2 Otoko Hill. Taken by our site engineer, it shows the 14 whaler beams, and 28 ground anchors inserted into the 12m high hill.

What’s a whaler beam? It’s a horizontal support that helps hold back soil on steep land around highways, keeping slopes stable and roads safe.

This recently finished project was all about stabilising the land around SH2. That included installing extensive drainage to stop water building up in the hills and channel it away.

The finished wall at Otoko Hill.

Rocking at SH35 Makatote

Check out the transformation at Makatote in Makarika Valley, just north of Te Puia Springs. These 2 underslips on SH35 have now been repaired, making the road safer and more reliable for everyone heading through.

Both sites required rock revetment solutions and culvert improvements to help manage waterflow and better protect the state highway in future weather events.

Before and after at Makatote slip #2.

Before and after at Makatote slip #3.

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:

• Bund – embankment that creates a barrier
• Buttress – supporting structure
• Counterfort drain – drain that improves slope stability by controlling groundwater 
• Gabion wall - baskets filled with rocks
• Hanbar – specially designed interlocking blocks
• 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

• Matawai Road – willow wall to stabilise slip.
• Otoko Hill (Site K) - overslip repairs.
• Hakanui Straight (formerly called Nesbitt’s Dip) project – flood improvements.

SH2 coming soon

• Otoko Hill (site M) - underslip repairs.

SH35 underway

• Hikuwai Bridge No.1 replacement – enabling (early) works.
• Mangahauini Gorge – river works, drainage and culvert upgrades, highway repair and rebuild.
• 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.
• Tōrere – underslip and overslip repairs.
• Paronga - D9 Gully Site – 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.
• Rotokautuku (Waiapu) Bridge repairs – strengthening works.

SH35 coming soon

• Rototahe – flood resilience.
• Rotokautuku (Waiapu) Bridge revetment – scour protection.
• Rotokautuku (Waiapu) Bridge – southern end strengthening.
• Maraehara – underslip repairs.
• Uawa River Scour – Two underslips to be repaired to reinstate state highway to 2 lanes.
• Kopuaroa – drainage improvements.
• Paronga (D9) – drainage improvements.

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.