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TREC Tairāwhiti recovery update

Issue 46

22 May 2026

Tēnā koe

In this issue we share more about kura (school) visits to Mangahauini Gorge, a super-sized delivery to Hikuwai Bridge and an update on revetment work at Rotokautuku (Waiapu) Bridge.

Early site investigations for our new January 2026 weather event recovery sites on State Highway 35 (SH35) from Te Araroa to Pōtaka are nearly complete. These investigations will help determine permanent repair solutions. TREC and NZ Transport Agency Waka Kotahi (NZTA) are both working across this section of SH35. We’ll keep sharing more updates on these projects in future newsletters.

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


	Learning by the awa at Mangahauini Gorge Seeing infrastructure being built up close is often the best way to understand it, spark curiosity, and even inspire future careers in construction. Recently, we were pleased to welcome 33 tamariki (children) aged 10–13 from Te Kura Kaupapa Māori o Ngā Taonga Tūturu ki Tokomaru, Hātea a Rangi School, and Mata School to our Mangahauini Gorge site on SH35 for an afternoon of learning, exploration, and fun. The visit was a follow up to TREC’s pōwhiri at Waiparapara Marae at the start of the project, where the students first saw small models of the hanbars (large specially shaped concrete blocks) which would be placed in the awa (river). For this visit tamariki headed down to the awa to see the hanbars now installed up close. They learnt how they are positioned in a special pattern in the river to create a new roughened channel. These 5–10 tonne concrete units are helping to steady the riverbed and protect SH35 from erosion during high river flows. The design has been developed in partnership with local iwi and hapū, with a strong focus on protecting the awa and surrounding whenua. Tamariki also got to experience life on a construction site first hand; climbing into diggers and learning about machinery and the people who operate them. Kaiako (teacher) Min McClutchie from Te Kura Kaupapa Māori o Ngā Taonga Tūturu ki Tokomaru said the visit left a lasting impression: "Our tauira are still buzzing. They thoroughly enjoyed the entire visit. Yes, many loved sitting in the digger, but many had lots of questions about the roles of different staff that were onsite." Tamariki visiting the Mangahauini Gorge project site.


	Makarangu dropout repairs for long-term protection Work is progressing well on the large dropout site 500 metres south of the main Mangahauini Gorge works on SH35. The team has started excavating the foundation at the northern end of the site to create a solid base for the new rock armour toe along the riverbank. Rocks recovered from the existing temporary rock bund (protective barrier) are being reused and carefully placed as part of this process, while the remaining temporary bund is progressively removed. Once the recycled rock from the existing bund has been used, additional rock will be used to complete the structure. This armour layer will help protect the riverbank from erosion and provide long-term stability during high river flows. Looking ahead, excavation will begin at the southern end of the site to prepare for the installation of rock barbs. These angled rock structures will help guide the river back towards the centre of the channel and reduce pressure on the bank beside SH35. This staged work is an important step in strengthening the river channel and protecting the highway from future storm damage. Reused rock being carefully placed to rebuild and strengthen the riverbank at the Makarangu dropout site in Mangahauini Gorge.


	Super-sized delivery at Hikuwai Bridge Work is progressing well at the new Hikuwai Bridge site on SH35. Crews are now focused on the final stages of the bridge substructure (everything below the bridge deck) ahead of the arrival and installation of the bridge girders. Girders are large steel support beams that form the foundation of the bridge deck. Their arrival signals the start of superstructure works (the parts of the bridge built above the supports and piers). Fabricated by Napier-based company Eastbridge, the girders started arriving this week - see a super-sized delivery in our video below. A total of 20 girder pieces will be transported to site in 12 truckloads over 6 weeks. These pieces will then be bolted into 12 complete girders weighing 30 tonnes before being lifted into position. The bridge spans include: Four northern girders measuring 21.3 metres A centre span measuring 38.6 metres Four southern girders measuring 38.3 metres Approximately 12 crane lifts will be required to place the girders onto the bridge structure. The installation marks a significant milestone for the Hikuwai Bridge project and another great step towards a permanent solution for communities. Crews are expected to complete girder installation by late June, weather permitting.


	Rotokautuku (Waiapu) Bridge works now in the safe zone Great progress is now being made at our Ruatoria site on SH35. This year’s weather events and river conditions have presented significant challenges here. Periods of heavy rain created high flows and strong currents in the Waiapu River. Crews are placing dolosse (large shaped concrete blocks) to protect the area beneath the Rotokautuku (Waiapu) Bridge, ensuring the Waiapu River no longer threatens the completed works. Reinstatement of the sheet pile walls to prevent scour (erosion) against the dolosse at either end has also been completed. Crews will continue dolosse and rock bag placement through to July, when these protection works to the riverbank and bridge above are expected to be complete. Dolosse and rock bags being placed at the Rotokautuku (Waiapu) Bridge revetment site.


	Site investigations nearing completion for SH35 new sites Following the January 2026 weather events, NZTA asked TREC to manage a number of design-and-construct projects on SH35 between Pōtaka and Te Araroa. Geotechnical ground investigations at these sites on SH35 north of Te Araroa are now almost complete. TREC crews are moving to the final investigation site at Punaruku Hill from Monday 25 May 2026 for approximately one week. We will be undertaking borehole testing in 4 locations in the road corridor at Punaruku. This includes borehole drilling for samples so our design team can understand the ground conditions to design permanent repairs to suit the conditions. There are also local contractors working for NZTA at Punaruku to make temporary drainage improvements. Thank you for driving with care around this site to help keep everyone safe. The Punaruku slip earlier this year.


	NZTA’s work at SH35 Waikura underslip site NZTA is managing work at Waikura underslip, which is being carried out by local contractors. The Waikura slip site initially suffered extensive damage when some of the road collapsed during the storm event in January. Initial work was carried out to make the road safe before the new cracking developed late last month. Emergency works have now been completed, and recovery work is getting underway. See NZTA’s recent update on this work. Works underway at Waikura underslip.

State highway snapshot

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

SH2 underway

Faram’s – counterfort drain installation.

SH35 underway

Hikuwai Bridge No.1 replacement.
Mangahauini Gabion Wall – Stage 2 – soil nails, buttress and rip rap at the bottom of the existing gabion wall.
Mangahauini Gorge – river works, drainage and culvert upgrades, highway repair and rebuild.
Rotokautuku (Waiapu) Bridge revetment – scour protection.
Maraehara – underslip repairs.
Uawa River – underslip repairs.

SH35 coming soon

Kopuaroa – drainage improvements.
Kopuaroa – pavement works.
Kemps Hill (Stage 3) - underslip repair.
TREC's January weather event sites between Pōtaka and Te Araroa - permanent repairs